The science
Quantum physics deals with the study of the behavior of the smallest things in our universe: subatomic particles. This is a relatively new science, only becoming one in the early 20th century after physicists began to wonder why they couldn't explain some of the effects of radiation. One of the innovators of the time, Max Planck, used the term "quanta" to study tiny particles with energy, hence the name "quantum physics". Planck noted that the amount of energy contained in electrons is not arbitrary, but conforms to the standards of "quantum" energy. One of the first results practical application this knowledge was the invention of the transistor.
Unlike the inflexible laws of standard physics, the rules of quantum physics can be broken. When scientists believe that they are dealing with one aspect of the study of matter and energy, there is new turn events, which reminds them of how unpredictable work can be in this area. However, even if they do not fully understand what is happening, they can use the results of their work to develop new technologies, which at times can only be called fantastic.
In the future, quantum mechanics could help keep military secrets as well as keep your bank account safe and secure from cyber thieves. Scientists are currently working on quantum computers, the capabilities of which go far beyond the limits of a conventional PC. Divided into subatomic particles items can be easily moved from one place to another in the blink of an eye. And perhaps quantum physics will be able to answer the most intriguing question about what the universe is made of and how life began.
Below are facts about how quantum physics can change the world. As Niels Bohr said: "Those who are not shocked by quantum mechanics simply have not yet understood how it works."
Turbulence management
Soon, perhaps thanks to quantum physics, it will be possible to eliminate the turbulent zones that cause you to spill juice on an airplane. By creating quantum turbulence in ultracold gas atoms in the lab, Brazilian scientists may be able to understand the workings of the turbulent zones encountered by planes and boats. For centuries, turbulence has baffled scientists because of the difficulty of recreating it in the laboratory.
Turbulence is caused by clumps of gas or liquid, but in nature it seems to form randomly and unexpectedly. Although turbulent zones can form in water and air, scientists have found that they can also form in ultracold gas atoms or in superfluid helium. By studying this phenomenon under controlled laboratory conditions, scientists may one day be able to accurately predict where turbulent zones will appear, and possibly control them in nature.
Spintronics
A new magnetic semiconductor developed at the Massachusetts Institute of Technology, could lead to even faster, energy-efficient electronic devices in the future. Called "spintronics," this technology uses the spin state of electrons to transmit and store information. While conventional electronic circuits only use the charge state of the electron, spintronics takes advantage of the electron's spin direction.
Processing information using spintronics circuits will allow data to be accumulated from two directions at once, which will also reduce the size of electronic circuits. This new material injects an electron into a semiconductor based on its spin orientation. The electrons pass through the semiconductor and become ready to be spin detectors on the exit side. The scientists say the new semiconductors can operate at room temperature and are optically transparent, meaning they can work with touch screens and solar panels. They also believe it will help inventors come up with even more feature-rich devices.
Parallel Worlds
Have you ever wondered what our life would be like if we had the ability to travel through time? Would you kill Hitler? Or join the Roman legions to see ancient world? However, while we're all fantasizing about what we'd do if we could go back in time, scientists at the University of California, Santa Barbara are already clearing the way to repair past grievances.
In an experiment in 2010, scientists managed to prove that an object can simultaneously exist in two different worlds. They isolated a tiny piece of metal and, under special conditions, found that it moved and stood still at the same time. However, someone may consider this observation as delirium caused by overwork, yet physicists say that observations of an object really show that it breaks up into two parts in the Universe - we see one of them and not the other. Theories of parallel worlds unanimously say that absolutely any object falls apart.
Now scientists are trying to figure out how to "jump over" the moment of collapse and enter the world that we do not see. This time travel to parallel universes should theoretically work, since quantum particles move both forward and backward in time. Now, all scientists have to do is build a time machine using quantum particles.
quantum dots
Soon, quantum physicists will be able to help doctors detect cancer cells in the body and pinpoint exactly where they have spread. Scientists have discovered that some small semiconductor crystals, called quantum dots, can glow when exposed to ultraviolet radiation and photographed with a special microscope. Then they were combined with a special material that was “attractive” to cancer cells. Upon entering the body, the luminous quantum dots were attracted to cancer cells, thus showing doctors exactly where to look. The glow continues for quite a long time, and for scientists, the process of adjusting the points to the characteristics of a particular type of cancer is relatively simple.
While high-tech science is certainly responsible for many medical advances, man has been dependent on many other means of fighting disease for centuries.
Prayer
It's hard to imagine what a Native American, a shamanic healer, and the pioneers of quantum physics could have in common. However, there is still something in common between them. Niels Bohr, one of the early explorers of this strange field of science, believed that much of what we call reality depends on the "observer effect", that is, the connection between what is happening and how we see it. This topic has given rise to the development of serious debates among quantum physicists, however, an experiment conducted by Bohr more than half a century ago confirmed his assumption.
All this means that our consciousness affects reality and can change it. The repeated words of the prayer and rituals of the shaman-healer's ceremony may be attempts to change the direction of the "wave" that creates reality. Most of the rites are also performed in the presence of multiple observers, indicating that the more "healing waves" come from the observers, the more powerful their effect on reality.
Object relationship
The interconnection of objects can further have a huge impact on solar energy. The interconnection of objects implies the quantum interdependence of atoms separated in real physical space. Physicists believe that the relationship may be formed in the part of plants responsible for photosynthesis, or the conversion of light into energy. The structures responsible for photosynthesis, the chromophores, can convert 95 percent of the light they receive into energy.
Scientists are now studying how this relationship at the quantum level can affect the creation of solar energy in the hope of creating efficient natural solar cells. The researchers also found that algae can use some of quantum mechanics to move the energy it receives from light, as well as store it in two places at the same time.
quantum computing
Other no less important aspect quantum physics can be applied to the computer realm, where a special type of superconducting element gives the computer unprecedented speed and power. The researchers explain that the element behaves like artificial atoms, as they can only either gain or lose energy by moving between discrete energy levels. The most complex atom has five levels of energy. This complex system ("kudit") has significant advantages over the operation of previous atoms, which had only two energy levels ("qubit"). Qudits and qubits are part of the bits used in standard computers. Quantum computers will use the principles of quantum mechanics in their work, which will allow them to perform calculations much faster and more accurately than traditional computers.
There is, however, a problem that may arise if quantum computing becomes a reality - cryptography, or the encoding of information.
quantum cryptography
Everything from your credit card number to top-secret military strategies is on the Internet, and a skilled hacker with enough knowledge and a powerful computer can empty your bank account or put the world's security at risk. A special encoding keeps this information secret, and computer scientists are constantly working to create new, more secure encoding methods.
Encoding information inside a single particle of light (photon) has long been the goal of quantum cryptography. It seemed that the scientists at the University of Toronto were already very close to creating this method, since they managed to encode the video. Encryption includes strings of zeros and ones, which are the "key". Adding a key once encodes the information, adding it again decodes it. If an outsider manages to get the key, then the information can be hacked. But even if the keys are used at the quantum level, the very fact of their use will certainly imply the presence of a hacker.
Teleportation
This is science fiction, nothing more. However, it was carried out, but only not with the participation of a person, but with the participation of large molecules. But therein lies the problem. Every molecule in the human body must be scanned from two sides. But this is unlikely to happen anytime soon. There is another problem: as soon as you scan a particle, according to the laws of quantum physics, you change it, that is, you have no way to make an exact copy of it.
This is where the interconnection of objects manifests itself. It links two objects as if they were one. We scan one half of the particle, and the teleported copy will be made by the other half. This will be an exact copy, since we did not measure the particle itself, we measured its twin. That is, the particle that we measured will be destroyed, but its exact copy will be reanimated by its twin.
Particles of God
Scientists are using their very huge creation, the Large Hadron Collider, to explore something extremely small but very important - the fundamental particles that are believed to underlie the origin of our universe.
God Particles are what scientists claim give mass to elementary particles (electrons, quarks and gluons). Experts believe that the particles of God must permeate all space, but so far the existence of these particles has not been proven.
Finding these particles would help physicists understand how the universe recovered from big bang and evolved into what we know about it today. It would also help explain how matter balances with antimatter. In short, isolating these particles will help explain everything.
QUANTUM MECHANICAL CONCEPTS
DESCRIPTIONS OF NATURE
In a sense, all modern physics there is quantum physics! It is, in fact, the result of "the latest revolution in natural science."
What does quantum physics study?
First of all, quantum physics is a theory that describes the properties of matter at the level of microphenomena. She explores the laws of motion of quantum objects, which are also called micro-objects.
The concept of a micro-object is one of the basic ones in quantum physics. These include molecules, atoms, atomic nuclei, elementary particles. Their characteristic feature is very small sizes - 10^ -8 cm and less. The most important characteristics of micro-objects include the rest mass and electric charge. The mass of an electron is me = 9.1 10^−28 g, the mass of a proton is 1836me, the neutron is 1839me, and the muon is 207me. Photon and neutrino have no rest mass - it is equal to zero. The value of the electric charge of any micro-object is a multiple of the value of the electron charge, equal to 1.6· 10^−19 C. Along with the charged ones, there are neutral micro-objects, the charge of which zero. The electric charge of a complex micro-object is equal to the algebraic sum of the charges of its constituent particles. One of the most important specific characteristics of microobjects is the spin (from English word"rotate"). Although the spin is interpreted as the angular momentum of a micro-object, not related to its motion as a whole, indestructible and independent of external conditions, it cannot be represented as a rotating top. It has a purely quantum nature - it has no analogues in classical physics. The presence of spin introduces significant features in the behavior of objects in the microworld.
Most micro-objects are unstable - they spontaneously, without any external influences, decay, turning into other, including elementary, particles. Instability is a specific, but not mandatory property of micro-objects. Along with unstable, there are also stable micro-objects: photon, electron, proton, neutrino, stable atomic nuclei, atoms and molecules in the ground state.
Quantum physics is still a theoretical basis modern teaching on the structure and properties of matter and field.
It is important to understand that quantum physics does not cancel the classical one, but contains it as its limiting case. In the transition from micro-objects to ordinary macroscopic objects, its laws become classical, and thus quantum physics has set the limits of applicability of classical physics. The transition from classical to quantum physics is a transition to a deeper level of consideration of matter.
Quantum physics has become an important step in building a modern physical picture of the world. She allowed to predict and explain huge number various phenomena - from processes occurring in atoms and atomic nuclei to macroscopic effects in solids; without it, it seems now impossible to understand the origin of the universe. The range of quantum physics is wide - from elementary particles to space objects. Without quantum physics, not only natural science, but also modern technology is unthinkable.
I think it's safe to say that no one understands quantum mechanics.
Physicist Richard Feynman
It is no exaggeration to say that the invention of semiconductor devices was a revolution. Not only is this an impressive technological achievement, but it also paved the way for events that will change modern society forever. Semiconductor devices are used in all kinds of microelectronic devices, including computers, certain types of medical diagnostic and treatment equipment, and popular telecommunications devices.
But behind this technological revolution is even more, a revolution in general science: the field quantum theory. Without this leap in understanding the natural world, the development of semiconductor devices (and more advanced electronic devices under development) would never have succeeded. Quantum physics is an incredibly complex branch of science. This chapter only provides a brief overview. When scientists like Feynman say "no one understands [it]" you can be sure it's real difficult topic. Without a basic understanding of quantum physics, or at least an understanding scientific discoveries that led to their development, it is impossible to understand how and why semiconductor electronic devices work. Most electronics textbooks try to explain semiconductors in terms of "classical physics", making them even more confusing to understand as a result.
Many of us have seen atomic model diagrams that look like the picture below.
Rutherford atom: negative electrons revolve around a small positive nucleus
Tiny particles of matter called protons and neutrons, make up the center of the atom; electrons revolve like planets around a star. The nucleus carries a positive electrical charge due to the presence of protons (neutrons have no electrical charge), while the balancing negative charge of an atom resides in the orbiting electrons. Negative electrons are attracted to positive protons like planets are attracted to the Sun, but the orbits are stable due to the movement of electrons. We owe this popular model of the atom to the work of Ernest Rutherford, who experimentally determined around 1911 that the positive charges of atoms are concentrated in a tiny, dense nucleus, and not evenly distributed along the diameter, as explorer J. J. Thomson had previously assumed.
Rutherford's scattering experiment consists of bombarding a thin gold foil with positively charged alpha particles, as shown in the figure below. Young graduate students H. Geiger and E. Marsden got unexpected results. The trajectory of some alpha particles was deviated by a large angle. Some alpha particles were scattered into reverse direction at an angle of almost 180°. Most of the particles passed through the gold foil without changing their trajectory, as if there was no foil at all. The fact that several alpha particles experienced large deviations in their trajectory indicates the presence of nuclei with a small positive charge.
Rutherford scattering: a beam of alpha particles is scattered by thin gold foil Although Rutherford's model of the atom was supported by experimental data better than Thomson's, it was still imperfect. Further attempts were made to determine the structure of the atom, and these efforts helped pave the way for the strange discoveries of quantum physics. Today our understanding of the atom is a bit more complex. Yet despite the revolution of quantum physics and its contributions to our understanding of the structure of the atom, Rutherford's depiction of the solar system as the structure of an atom has taken root in popular consciousness to the extent that it persists in educational fields, even if it is misplaced.
Consider it short description electrons in an atom, taken from a popular electronics textbook:
The spinning negative electrons are attracted to the positive nucleus, which leads us to the question of why the electrons don't fly into the nucleus of the atom. The answer is that the rotating electrons remain in their stable orbit due to two equal but opposite forces. The centrifugal force acting on the electrons is directed outward, and the attractive force of the charges is trying to pull the electrons towards the nucleus.
In accordance with Rutherford's model, the author considers electrons to be solid pieces of matter occupying round orbits, their inward attraction to the oppositely charged nucleus is balanced by their movement. The use of the term "centrifugal force" is technically incorrect (even for orbiting planets), but this is easily forgiven due to the popular acceptance of the model: in fact, there is no such thing as force, repulsiveany rotating body from the center of its orbit. It seems that this is so because the inertia of the body tends to keep its motion in a straight line, and since the orbit is a constant deviation (acceleration) from rectilinear motion, there is a constant inertial reaction to any force that attracts the body to the center of the orbit (centripetal), be it gravity, electrostatic attraction, or even the tension of a mechanical bond.
However, the real problem with this explanation in the first place is the idea of electrons moving in circular orbits. A proven fact that accelerated electric charges emit electromagnetic radiation, this fact was known even in Rutherford's time. As rotary motion is a form of acceleration (a rotating object in constant acceleration, pulling the object away from its normal rectilinear motion), the electrons in the rotating state should emit radiation like mud from a spinning wheel. Electrons accelerated along circular paths in particle accelerators called synchrotrons are known to do this, and the result is called synchrotron radiation. If electrons were to lose energy in this way, their orbits would eventually be disrupted, and as a result they would collide with a positively charged nucleus. However, inside atoms this usually does not happen. Indeed, electronic "orbits" are surprisingly stable over a wide range of conditions.
In addition, experiments with "excited" atoms have shown that electromagnetic energy is emitted by an atom only at certain frequencies. Atoms are "excited" by external influences such as light, known to absorb energy and return electromagnetic waves at certain frequencies, like a tuning fork that doesn't ring at a certain frequency until it's struck. When the light emitted by an excited atom is divided by a prism into its component frequencies (colors), individual lines of colors in the spectrum are found, the spectral line pattern is unique to a chemical element. This phenomenon is commonly used to identify chemical elements, and even to measure the proportions of each element in a compound or chemical mixture. According to the solar system of the Rutherford atomic model (relative to electrons, as pieces of matter, freely rotating in an orbit with some radius) and the laws of classical physics, excited atoms must return energy in an almost infinite frequency range, and not at selected frequencies. In other words, if Rutherford's model was correct, then there would be no "tuning fork" effect, and the color spectrum emitted by any atom would appear as a continuous band of colors, rather than as several separate lines.
Bohr's model of the hydrogen atom (with the orbits drawn to scale) assumes that electrons are only in discrete orbits. Electrons moving from n=3,4,5 or 6 to n=2 are displayed on a series of Balmer spectral lines A researcher named Niels Bohr tried to improve Rutherford's model after studying it in Rutherford's laboratory for several months in 1912. Trying to reconcile the results of other physicists (notably Max Planck and Albert Einstein), Bohr suggested that each electron had a certain, specific amount of energy, and that their orbits were distributed in such a way that each of them could occupy certain places around the nucleus, like balls. , fixed on circular paths around the nucleus, and not as free-moving satellites, as previously assumed (figure above). In deference to the laws of electromagnetism and accelerating charges, Bohr referred to "orbits" as stationary states to avoid the interpretation that they were mobile.
Although Bohr's ambitious attempt to rethink the structure of the atom, which was more consistent with experimental data, was a milestone in physics, it was not completed. His mathematical analysis predicted the results of experiments better than those performed according to previous models, but there were still unanswered questions about whether why the electrons must behave in such a strange way. The statement that electrons existed in stationary quantum states around the nucleus correlated better with experimental data than Rutherford's model, but did not say what causes the electrons to take these special conditions. The answer to this question was to come from another physicist, Louis de Broglie, some ten years later.
De Broglie suggested that electrons, like photons (particles of light), have both the properties of particles and the properties of waves. Based on this assumption, he suggested that the analysis of rotating electrons in terms of waves is better than in terms of particles, and can give more insight into their quantum nature. Indeed, another breakthrough was made in understanding.
A string vibrating at a resonant frequency between two fixed points forms a standing wave The atom, according to de Broglie, consisted of standing waves, a phenomenon well known to physicists in various forms. Like the plucked string of a musical instrument (pictured above), vibrating at a resonant frequency, with "knots" and "anti-knots" in stable places along its length. De Broglie imagined electrons around atoms as waves curved into a circle (figure below).
"Rotating" electrons like a standing wave around the nucleus, (a) two cycles in an orbit, (b) three cycles in an orbit Electrons can only exist in certain, specific "orbits" around the nucleus, because they are the only distances where the ends of the wave coincide. At any other radius, the wave will collide destructively with itself and thus cease to exist.
De Broglie's hypothesis provided both a mathematical framework and a convenient physical analogy to explain the quantum states of electrons within an atom, but his model of the atom was still incomplete. For several years, physicists Werner Heisenberg and Erwin Schrödinger, working independently, worked on the concept of de Broglie's wave-particle duality in order to create more rigorous mathematical models subatomic particles.
This theoretical advance from the primitive model standing wave de Broglie to models of the Heisenberg matrix and differential equation Schrödinger was given the name quantum mechanics, it introduced a rather shocking characteristic to the world of subatomic particles: a sign of probability, or uncertainty. According to the new quantum theory, it was impossible to determine the exact position and exact momentum of a particle at one moment. A popular explanation for this "uncertainty principle" was that there was a measurement error (that is, by trying to accurately measure the position of an electron, you interfere with its momentum, and therefore cannot know what it was before you started measuring the position, and vice versa). The sensational conclusion of quantum mechanics is that particles do not have exact positions and momenta, and because of the relationship of these two quantities, their combined uncertainty will never decrease below a certain minimum value.
This form of "uncertainty" connection also exists in fields other than quantum mechanics. As discussed in the Signals chapter alternating current Mixed Frequency” in Volume 2 of this book series, there are mutually exclusive relationships between the confidence in the time domain data of a waveform and its frequency domain data. Simply put, the more we know its component frequencies, the less accurately we know its amplitude over time, and vice versa. Quoting myself:
A signal of infinite duration (an infinite number of cycles) can be analyzed with absolute precision, but what fewer cycles available to the computer for analysis, the less the accuracy of the analysis ... The fewer periods of the signal, the less the accuracy of its frequency. Taking this concept to its logical extreme, a short pulse (not even a full period of a signal) doesn't really have a defined frequency, it's an infinite range of frequencies. This principle is common to all wave phenomena, and not only to variable voltages and currents.
To accurately determine the amplitude of a changing signal, we must measure it in a very short amount of time. However, doing this limits our knowledge of the frequency of the wave (a wave in quantum mechanics does not need to be similar to a sine wave; such similarity is a special case). On the other hand, in order to determine the frequency of a wave with great accuracy, we must measure it over a large number of periods, which means that we will lose sight of its amplitude at any given moment. Thus, we cannot simultaneously know the instantaneous amplitude and all frequencies of any wave with unlimited accuracy. Another oddity, this uncertainty is much greater than the inaccuracy of the observer; it is in the very nature of the wave. This is not the case, although it would be possible, given the appropriate technology, to provide accurate measurements of both instantaneous amplitude and frequency simultaneously. In a literal sense, a wave cannot have the exact instantaneous amplitude and the exact frequency at the same time.
The minimum uncertainty of particle position and momentum expressed by Heisenberg and Schrödinger has nothing to do with a limitation in measurement; rather, it is an intrinsic property of the nature of the wave-particle duality of the particle. Therefore, electrons do not actually exist in their "orbits" as well-defined particles of matter, or even as well-defined waveforms, but rather as "clouds" - a technical term. wave function probability distributions, as if each electron were "scattered" or "smeared out" over a range of positions and momenta.
This radical view of electrons as indeterminate clouds initially contradicts the original principle of the quantum states of electrons: electrons exist in discrete, definite "orbits" around the nucleus of an atom. This new view, after all, was the discovery that led to the formation and explanation of quantum theory. How strange it seems that a theory created to explain the discrete behavior of electrons ends up declaring that electrons exist as "clouds" and not as separate pieces of matter. However, the quantum behavior of electrons does not depend on electrons having certain values of coordinates and momentum, but on other properties called quantum numbers. In essence, quantum mechanics dispenses with the common concepts of absolute position and absolute moment, and replaces them with absolute concepts of types that have no analogues in common practice.
Even though electrons are known to exist in disembodied, "cloudy" forms of distributed probability, rather than separate pieces of matter, these "clouds" have slightly different characteristics. Any electron in an atom can be described by four numerical measures (the quantum numbers mentioned earlier), called main (radial), orbital (azimuth), magnetic and spin numbers. Below is a brief overview of the meaning of each of these numbers:
Principal (radial) quantum number: denoted by a letter n, this number describes the shell on which the electron resides. The electron "shell" is a region of space around the nucleus of an atom in which electrons can exist, corresponding to de Broglie and Bohr's stable "standing wave" models. Electrons can "jump" from shell to shell, but cannot exist between them.
The principal quantum number must be a positive integer (greater than or equal to 1). In other words, the principal quantum number of an electron cannot be 1/2 or -3. These integers were not chosen arbitrarily, but through experimental evidence of the light spectrum: the different frequencies (colors) of light emitted by excited hydrogen atoms follow a mathematical relationship depending on specific integer values, as shown in the figure below.
Each shell has the ability to hold multiple electrons. An analogy for electron shells is the concentric rows of seats in an amphitheater. Just as a person sitting in an amphitheater must choose a row to sit down (he cannot sit between the rows), electrons must "choose" a particular shell in order to "sit down". Like rows in an amphitheatre, the outer shells hold more electrons than the shells closer to the center. Also, the electrons tend to find the smallest available shell, just as people in an amphitheater look for the place closest to the central stage. The higher the shell number, the more energy the electrons have on it.
The maximum number of electrons that any shell can hold is described by the equation 2n 2 , where n is the principal quantum number. Thus, the first shell (n = 1) can contain 2 electrons; the second shell (n = 2) - 8 electrons; and the third shell (n = 3) - 18 electrons (figure below).
The main quantum number n and the maximum number of electrons are related by the formula 2(n 2). Orbits are not to scale. The electron shells in the atom were denoted by letters rather than numbers. The first shell (n = 1) was designated K, the second shell (n = 2) L, the third shell (n = 3) M, the fourth shell (n = 4) N, the fifth shell (n = 5) O, the sixth shell ( n = 6) P, and the seventh shell (n = 7) B.
Orbital (azimuth) quantum number: a shell composed of subshells. Some may find it more convenient to think of subshells as simple sections of shells, like lanes dividing a road. Subshells are much weirder. Subshells are regions of space where electron "clouds" can exist, and in fact the various subshells have various forms. The first subshell is in the shape of a ball (Figure below (s)), which makes sense when visualized as an electron cloud surrounding the nucleus of an atom in three dimensions.
The second subshell resembles a dumbbell, consisting of two "petals" connected at one point near the center of the atom (figure below (p)).
The third subshell usually resembles a set of four "petals" clustered around the nucleus of an atom. These subshell shapes resemble pictorial representations of antenna patterns, with onion-like lobes extending from the antenna into various directions(Figure below (d)).
Orbitals: (s) triple symmetry;
(p) Shown: p x , one of three possible orientations (p x , p y , p z), along the respective axes;
(d) Shown: d x 2 -y 2 is similar to d xy , d yz , d xz . Shown: d z 2 . Number of possible d-orbitals: five.
Valid values orbital quantum numbers are positive integers, as for the principal quantum number, but also include zero. These quantum numbers for electrons are denoted by the letter l. The number of subshells is equal to the principal quantum number of the shell. Thus, the first shell (n = 1) has one subshell with number 0; the second shell (n = 2) has two subshells numbered 0 and 1; the third shell (n = 3) has three subshells numbered 0, 1 and 2.
The old subshell convention used letters rather than numbers. In this format, the first subshell (l = 0) was denoted s, the second subshell (l = 1) was denoted p, the third subshell (l = 2) was denoted d, and the fourth subshell (l = 3) was denoted f. The letters came from the words: sharp, principal, diffuse and Fundamental. You can still see these designations in many periodic tables used to designate electronic configuration external ( valence) shells of atoms.
(a) the Bohr representation of the silver atom, (b) Orbital representation of Ag with division of shells into subshells (orbital quantum number l).
This diagram does not imply anything about the actual position of the electrons, but only represents the energy levels.
Magnetic quantum number: The magnetic quantum number for the electron classifies the orientation of the electron subshell figure. The "petals" of the subshells can be directed in several directions. These different orientations are called orbitals. For the first subshell (s; l = 0), which resembles a sphere, "direction" is not specified. For a second (p; l = 1) subshell in each shell that resembles a dumbbell pointing in three possible directions. Imagine three dumbbells intersecting at the origin, each pointing along its own axis in a triaxial coordinate system.
Valid values for a given quantum number consist of integers ranging from -l to l, and this number is denoted as m l in atomic physics and z in nuclear physics. To calculate the number of orbitals in any subshell, double the subshell number and add 1, (2∙l + 1). For example, the first subshell (l = 0) in any shell contains one orbital numbered 0; the second subshell (l = 1) in any shell contains three orbitals with numbers -1, 0 and 1; the third subshell (l = 2) contains five orbitals numbered -2, -1, 0, 1 and 2; etc.
Like the principal quantum number, the magnetic quantum number arose directly from experimental data: the Zeeman effect, the separation of spectral lines by exposing an ionized gas to magnetic field, hence the name "magnetic" quantum number.
Spin quantum number: like the magnetic quantum number, this property of the electrons of an atom was discovered through experiments. Careful observation of the spectral lines showed that each line was in fact a pair of very closely spaced lines, it has been suggested that this so-called fine structure was the result of each electron "spinning" around its own axis, like a planet. Electrons with different "spins" would give off slightly different frequencies of light when excited. The spinning electron concept is now obsolete, being more appropriate for the (incorrect) view of electrons as individual particles of matter rather than as "clouds", but the name remains.
Spin quantum numbers are denoted as m s in atomic physics and sz in nuclear physics. Each orbital in each subshell can have two electrons in each shell, one with spin +1/2 and the other with spin -1/2.
Physicist Wolfgang Pauli developed a principle that explains the ordering of electrons in an atom according to these quantum numbers. His principle, called Pauli exclusion principle, states that two electrons in the same atom cannot occupy the same quantum states. That is, each electron in an atom has a unique set quantum numbers. This limits the number of electrons that can occupy any given orbital, subshell, and shell.
This shows the arrangement of electrons in a hydrogen atom:
With one proton in the nucleus, the atom accepts one electron for its electrostatic balance (the proton's positive charge is exactly balanced by the electron's negative charge). This electron is in the lower shell (n = 1), the first subshell (l = 0), in the only orbital (spatial orientation) of this subshell (m l = 0), with a spin value of 1/2. The general method of describing this structure is by enumerating the electrons according to their shells and subshells, according to a convention called spectroscopic notation. In this notation, the shell number is shown as an integer, the subshell as a letter (s,p,d,f), and the total number of electrons in the subshell (all orbitals, all spins) as a superscript. Thus, hydrogen, with its single electron placed at the base level, is described as 1s 1 .
Moving on to the next atom (in order of atomic number), we get the element helium:
A helium atom has two protons in its nucleus, which requires two electrons to balance the double positive electrical charge. Since two electrons - one with spin 1/2 and the other with spin -1/2 - are in the same orbital, the electronic structure of helium does not require additional subshells or shells to hold the second electron.
However, an atom requiring three or more electrons will need additional subshells to hold all the electrons, since only two electrons can be on the bottom shell (n = 1). Consider the next atom in the sequence of increasing atomic numbers, lithium:
The lithium atom uses part of the capacitance L of the shell (n = 2). This shell actually has a total capacity of eight electrons (maximum shell capacity = 2n 2 electrons). If we consider the structure of an atom with a completely filled L shell, we see how all combinations of subshells, orbitals, and spins are occupied by electrons:
Often, when assigning a spectroscopic notation to an atom, any fully filled shells are skipped, rather than filled shells and filled shells. top level are indicated. For example, the element neon (shown in the figure above), which has two completely filled shells, can be described spectrally simply as 2p 6 rather than as 1s 22 s 22 p 6 . Lithium, with its fully filled K shell and a single electron in the L shell, can simply be described as 2s 1 rather than 1s 22 s 1 .
The omission of fully populated lower-level shells is not only for convenience of notation. It also illustrates a basic principle of chemistry: the chemical behavior of an element is primarily determined by its unfilled shells. Both hydrogen and lithium have on their outer shells one electron (as 1 and 2s 1 respectively), that is, both elements have similar properties. Both are highly reactive, and react in almost identical ways (binding to similar elements under similar conditions). Doesn't have of great importance that lithium has a completely filled K-shell under an almost free L-shell: the unfilled L-shell is the one that determines its chemical behavior.
Elements that have completely filled outer shells are classified as noble and are characterized by an almost complete lack of reaction with other elements. These elements were classified as inert when they were considered not to react at all, but they are known to form compounds with other elements under certain conditions.
Since elements with the same electron configurations in their outer shells have similar Chemical properties, Dmitri Mendeleev organized the chemical elements in the table accordingly. This table is known as , and modern tables follow this general view shown in the figure below.
Periodic table of chemical elements Dmitri Mendeleev, a Russian chemist, was the first to develop the periodic table of elements. Despite the fact that Mendeleev organized his table according to atomic mass, but not atomic number, and created a table that was not as useful as modern periodic tables, his development stands as an excellent example of scientific evidence. Seeing patterns of periodicity (similar chemical properties according to atomic mass), Mendeleev hypothesized that all elements must fit into this ordered pattern. When he discovered "empty" places in the table, he followed the logic of the existing order and assumed the existence of yet unknown elements. The subsequent discovery of these elements confirmed the scientific correctness of Mendeleev's hypothesis, further discoveries led to the form of the periodic table that we use now.
Like this should work science: hypotheses lead to logical conclusions and are accepted, changed or rejected depending on the consistency of experimental data with their conclusions. Any fool can formulate a hypothesis after the fact to explain the available experimental data, and many do. What distinguishes a scientific hypothesis from post hoc speculation is the prediction of future experimental data that has not yet been collected, and possibly the refutation of that data as a result. Boldly lead the hypothesis to its logical conclusion(s) and the attempt to predict the results of future experiments is not a dogmatic leap of faith, but rather a public test of this hypothesis, an open challenge to the opponents of the hypothesis. In other words, scientific hypotheses are always "risky" due to an attempt to predict the results of experiments that have not yet been done, and therefore can be refuted if the experiments do not go as expected. Thus, if a hypothesis correctly predicts the results of repeated experiments, it is disproven.
Quantum mechanics, first as a hypothesis and then as a theory, has been extremely successful in predicting the results of experiments, hence a high degree scientific trust. Many scientists have reason to believe that this is an incomplete theory, since its predictions are more true at microphysical scales than macroscopic ones, but nevertheless, it is an extremely useful theory for explaining and predicting the interaction of particles and atoms.
As you have seen in this chapter, quantum physics is essential in describing and predicting many different phenomena. In the next section, we will see its meaning in electrical conductivity solids, including semiconductors. Simply put, nothing in chemistry or physics solid body makes no sense in the popular theoretical structure electrons, existing as separate particles of matter, circling around the nucleus of an atom, like miniature satellites. When electrons are viewed as "wave functions" existing in certain, discrete states that are regular and periodic, then the behavior of matter can be explained.
Summing up
The electrons in atoms exist in "clouds" of distributed probability, and not as discrete particles of matter revolving around the nucleus, like miniature satellites, as common examples show.
Individual electrons around the nucleus of an atom tend to unique "states" described by four quantum numbers: principal (radial) quantum number, known as shell; orbital (azimuth) quantum number, known as subshell; magnetic quantum number describing orbital(subshell orientation); and spin quantum number, or simply spin. These states are quantum, that is, “between them” there are no conditions for the existence of an electron, except for states that fit into the quantum numbering scheme.
Glanoe (radial) quantum number (n) describes a basic level of or the shell containing the electron. The greater this number, the greater the radius of the electron cloud from the nucleus of the atom, and the greater the energy of the electron. Principal quantum numbers are integers (positive integers)
Orbital (azimuthal) quantum number (l) describes the shape of an electron cloud in a particular shell or level and is often known as a "subshell". In any shell, there are as many subshells (forms of an electron cloud) as the main quantum number of the shell. Azimuthal quantum numbers are positive integers starting from zero and ending with a number less than the main quantum number by one (n - 1).
Magnetic quantum number (m l) describes what orientation the subshell (electron cloud shape) has. Subshells can have as many different orientations as twice the subshell number (l) plus 1, (2l+1) (that is, for l=1, m l = -1, 0, 1), and each unique orientation is called an orbital. These numbers are integers starting from a negative value of the subshell number (l) through 0 and ending with a positive value of the subshell number.
Spin Quantum Number (m s) describes another property of the electron and can take the values +1/2 and -1/2.
Pauli exclusion principle says that two electrons in an atom cannot share the same set of quantum numbers. Therefore, there can be at most two electrons in each orbital (spin=1/2 and spin=-1/2), 2l+1 orbitals in each subshell, and n subshells in each shell, and no more.
Spectroscopic notation is a convention for the electronic structure of an atom. Shells are shown as integers, followed by subshell letters (s, p, d, f) with superscript numbers indicating the total number of electrons found in each respective subshell.
The chemical behavior of an atom is determined solely by electrons in unfilled shells. Low-level shells that are completely full have little or no effect on chemical characteristics linking elements.
Elements with completely filled electron shells are almost completely inert, and are called noble elements (previously known as inert).
No one in this world understands what quantum mechanics is. This is perhaps the most important thing to know about her. Of course, many physicists have learned to use the laws and even predict phenomena based on quantum computing. But it is still unclear why the observer of the experiment determines the behavior of the system and forces it to take one of two states.
Here are some examples of experiments with results that will inevitably change under the influence of the observer. They show that quantum mechanics practically deals with the intervention of conscious thought in material reality.
There are many interpretations of quantum mechanics today, but the Copenhagen interpretation is perhaps the best known. In the 1920s, its general postulates were formulated by Niels Bohr and Werner Heisenberg.
The basis of the Copenhagen interpretation was the wave function. This is a mathematical function containing information about all possible states of a quantum system in which it exists simultaneously. According to the Copenhagen Interpretation, the state of a system and its position relative to other states can only be determined by observation (the wave function is only used to mathematically calculate the probability of the system being in one state or another).
It can be said that after observation, a quantum system becomes classical and immediately ceases to exist in states other than the one in which it was observed. This conclusion found its opponents (remember the famous Einstein's "God does not play dice"), but the accuracy of calculations and predictions still had its own.
Nevertheless, the number of supporters of the Copenhagen Interpretation is declining, and main reason this is the mysterious instantaneous collapse of the wave function during the experiment. Erwin Schrödinger's famous thought experiment with a poor cat should demonstrate the absurdity of this phenomenon. Let's remember the details.
Inside the black box sits a black cat and with it a vial of poison and a mechanism that can release the poison randomly. For example, a radioactive atom during decay can break a bubble. Exact time the decay of the atom is unknown. Only the half-life is known, during which decay occurs with a probability of 50%.
Obviously, for an external observer, the cat inside the box is in two states: it is either alive, if everything went well, or dead, if the decay has occurred and the vial has broken. Both of these states are described by the cat's wave function, which changes over time.
The more time has passed, the more likely it is that radioactive decay has occurred. But as soon as we open the box, the wave function collapses and we immediately see the results of this inhumane experiment.
In fact, until the observer opens the box, the cat will endlessly balance between life and death, or be both alive and dead. Its fate can only be determined as a result of the observer's actions. This absurdity was pointed out by Schrödinger.
According to a survey of famous physicists by The New York Times, the electron diffraction experiment is one of the most amazing studies in the history of science. What is its nature? There is a source that emits a beam of electrons onto a photosensitive screen. And there is an obstacle in the way of these electrons, a copper plate with two slots.
What picture can we expect on the screen if electrons are usually represented to us as small charged balls? Two stripes opposite the slots in the copper plate. But in fact, a much more complex pattern of alternating white and black stripes appears on the screen. This is due to the fact that when passing through the slit, electrons begin to behave not only as particles, but also as waves (photons or other light particles that can be a wave at the same time behave in the same way).
These waves interact in space, colliding and reinforcing each other, and as a result, a complex pattern of alternating light and dark stripes is displayed on the screen. At the same time, the result of this experiment does not change, even if the electrons pass one by one - even one particle can be a wave and pass through two slits at the same time. This postulate was one of the main ones in the Copenhagen interpretation of quantum mechanics, when particles can simultaneously demonstrate their "ordinary" physical properties and exotic properties like a wave.
But what about the observer? It is he who makes this confusing story even more confusing. When physicists in experiments like this tried to use instruments to determine which slit an electron was actually going through, the picture on the screen changed dramatically and became “classical”: with two illuminated sections directly opposite the slits, without any alternating stripes.
The electrons seemed reluctant to reveal their wave nature to the watchful eye of onlookers. It looks like a mystery shrouded in darkness. But there is a simpler explanation: the observation of the system cannot be carried out without physical influence on her. We will discuss this later.
2. Heated fullerenes
Experiments on particle diffraction were carried out not only with electrons, but also with other, much larger objects. For example, fullerenes were used, large and closed molecules consisting of several tens of carbon atoms. Recently, a group of scientists from the University of Vienna, led by Professor Zeilinger, tried to include an element of observation in these experiments. To do this, they irradiated moving fullerene molecules with laser beams. Then, heated by an external source, the molecules began to glow and inevitably reflect their presence to the observer.
Along with this innovation, the behavior of molecules has also changed. Prior to such a comprehensive observation, fullerenes avoided obstacles quite successfully (showing wave properties), similar to the previous example with electrons hitting the screen. But with the presence of an observer, fullerenes began to behave like perfectly law-abiding physical particles.
3. Cooling measurement
One of the most famous laws in the world of quantum physics is the Heisenberg uncertainty principle, according to which it is impossible to determine the speed and position of a quantum object at the same time. The more accurately we measure the momentum of a particle, the less accurately we can measure its position. However, in our macroscopic real world, the validity of quantum laws acting on tiny particles usually goes unnoticed.
Recent experiments by Prof. Schwab from the USA make a very valuable contribution to this field. Quantum effects in these experiments were demonstrated not at the level of electrons or fullerene molecules (which have an approximate diameter of 1 nm), but on larger objects, a tiny aluminum ribbon. This tape was fixed on both sides so that its middle was in a suspended state and could vibrate under external influence. In addition, a device capable of accurately recording the position of the tape was placed nearby. As a result of the experiment, several interesting things were discovered. Firstly, any measurement related to the position of the object and observation of the tape affected it, after each measurement the position of the tape changed.
The experimenters determined the coordinates of the tape with high accuracy, and thus, in accordance with the Heisenberg principle, changed its speed, and hence the subsequent position. Secondly, and quite unexpectedly, some measurements led to a cooling of the tape. Thus, an observer can change the physical characteristics of objects by their mere presence.
4. Freezing particles
As you know, unstable radioactive particles decay not only in experiments with cats, but also on their own. Each particle has an average lifetime, which, as it turns out, can increase under the watchful eye of an observer. This quantum effect was predicted back in the 60s, and its brilliant experimental proof appeared in a paper published by a group led by Nobel laureate in physics Wolfgang Ketterle of the Massachusetts Institute of Technology.
In this work, the decay of unstable excited rubidium atoms was studied. Immediately after the preparation of the system, the atoms were excited using laser beam. The observation took place in two modes: continuous (the system was constantly exposed to small light pulses) and pulsed (the system was irradiated from time to time with more powerful pulses).
The results obtained were in full agreement with the theoretical predictions. External light effects slow down the decay of particles, returning them to their original state, which is far from the state of decay. The magnitude of this effect also coincided with the predictions. The maximum lifetime of unstable excited rubidium atoms increased by a factor of 30.
5. Quantum mechanics and consciousness
Electrons and fullerenes cease to show their wave properties, aluminum plates cool down, and unstable particles slow down their decay. The watchful eye of the beholder literally changes the world. Why can't this be evidence of the involvement of our minds in the work of the world? Perhaps Carl Jung and Wolfgang Pauli (Austrian physicist, Nobel laureate, pioneer of quantum mechanics) were right, after all, when they said that the laws of physics and consciousness should be considered as complementary to each other?
We are one step away from recognizing that the world around us is simply an illusory product of our mind. The idea is scary and tempting. Let's try to turn to physicists again. Especially in last years when less and less less people believe the Copenhagen interpretation of quantum mechanics with its mysterious wave function collapses, turning to a more mundane and reliable decoherence.
The fact is that in all these experiments with observations, the experimenters inevitably influenced the system. They lit it with a laser and installed measuring instruments. They were united by an important principle: you cannot observe a system or measure its properties without interacting with it. Any interaction is a process of modifying properties. Especially when a tiny quantum system is exposed to colossal quantum objects. Some eternally neutral Buddhist observer is impossible in principle. And here the term "decoherence" comes into play, which is irreversible from the point of view of thermodynamics: the quantum properties of a system change when interacting with another large system.
During this interaction, the quantum system loses its original properties and becomes classical, as if "obeying" a large system. This also explains the paradox of Schrödinger's cat: a cat is too much big system, so it cannot be isolated from the rest of the world. The very design of this thought experiment is not entirely correct.
In any case, if we assume the reality of the act of creation by consciousness, decoherence seems to be a much more convenient approach. Perhaps even too convenient. With this approach, the entire classical world becomes one big consequence of decoherence. And as the author of one of the most famous books in the field stated, such an approach logically leads to statements like "there are no particles in the world" or "there is no time at a fundamental level."
What is the truth: in the creator-observer or powerful decoherence? We need to choose between two evils. Nevertheless, scientists are becoming increasingly convinced that quantum effects are manifestations of our mental processes. And where observation ends and reality begins depends on each of us.
According to topinfopost.com
An unprepared listener is frightened from the very beginning of acquaintance. It is strange and illogical, even for the physicists who deal with it every day. But she is not incomprehensible. If you are interested in quantum physics, there are actually six key concepts from it that you need to keep in mind. No, they are not related. And these are not thought experiments. Just wind them around your mustache and quantum physics will be much easier to understand.
There are many places to start this discussion, and this is as good as the others: everything in our universe has the nature of both particles and waves at the same time. If one could say about magic this way: "All these are waves, and only waves," that would be a wonderful poetic description of quantum physics. In fact, everything in this universe has a wave nature.
Of course, also everything in the universe has the nature of particles. Sounds weird, but it is.
Describing real objects as particles and waves at the same time would be somewhat inaccurate. Strictly speaking, the objects described by quantum physics are not particles and waves, but rather belong to the third category, which inherits the properties of waves (frequency and wavelength, along with propagation in space) and some properties of particles (they can be counted and localized to a certain degree ). This leads to a lively debate in the physics community about whether it is even correct to speak of light as a particle; not because there is a contradiction in whether light has a particle nature, but because calling photons "particles" and not "excitations of a quantum field" is misleading students. However, this also applies to whether electrons can be called particles, but such disputes will remain in purely academic circles.
This "third" nature of quantum objects is reflected in the sometimes confusing language of physicists who discuss quantum phenomena. The Higgs boson was discovered as a particle at the Large Hadron Collider, but you've probably heard the phrase "Higgs field", such a delocalized thing that fills all of space. This is because under certain conditions, such as particle collision experiments, it is more appropriate to discuss excitations of the Higgs field than to characterize the particle, while under other conditions, such as general discussions of why certain particles have mass, it is more appropriate to discuss physics in terms of interactions with the quantum a field of universal proportions. It's simple different languages describing the same mathematical objects.
Quantum physics is discrete
Everything in the name of physics - the word "quantum" comes from the Latin "how much" and reflects the fact that quantum models always include something coming in discrete quantities. The energy contained in a quantum field comes in multiples of some fundamental energy. For light, this is associated with the frequency and wavelength of the light—high-frequency, short-wavelength light has a huge characteristic energy, while low-frequency, long-wavelength light has little characteristic energy.
In both cases, meanwhile, the total energy contained in a separate light field is an integer multiple of this energy - 1, 2, 14, 137 times - and there are no strange fractions like one and a half, "pi" or the square root of two. This property is also observed in the discrete energy levels of atoms, and the energy bands are specific - some energy values are allowed, others are not. Atomic clocks work thanks to the discreteness of quantum physics, using the frequency of light associated with the transition between two allowed states in cesium, which allows you to keep time at the level necessary for the "second jump".
Ultra-precise spectroscopy can also be used to search for things like dark matter, and remains part of the motivation for the institute's work on low-energy fundamental physics.
It's not always obvious - even some things that are quantum in principle, like blackbody radiation, are associated with continuous distributions. But upon closer examination and when connecting a deep mathematical apparatus quantum theory gets even weirder.
Quantum physics is probabilistic
One of the most surprising and (at least historically) controversial aspects of quantum physics is that it is impossible to predict with certainty the outcome of a single experiment with a quantum system. When physicists predict the outcome of a particular experiment, their prediction is in the form of the probability of finding each of the particular possible outcomes, and comparisons between theory and experiment always involve deriving a probability distribution from many repeated experiments.
The mathematical description of a quantum system, as a rule, takes the form of a "wave function", represented in the equations of the Greek beech psi: Ψ. There are many discussions about what exactly the wave function is, and they have divided physicists into two camps: those who see the wave function as a real physical thing (ontic theorists), and those who believe that the wave function is solely an expression of our knowledge (or lack thereof) regardless of the underlying state of a particular quantum object (epistemic theorists).
In each class of the underlying model, the probability of finding a result is determined not by the wave function directly, but by the square of the wave function (roughly speaking, it is still the same; the wave function is a complex mathematical object (and therefore includes imaginary numbers like square root or its negative variant), and the operation of getting the probability is a bit more complicated, but "the square of the wave function" is enough to get the basic gist of the idea). This is known as the Born rule after German physicist Max Born, who first calculated it (in a footnote to a 1926 work) and surprised many people with its ugly incarnation. There is a lot of work going on to try to derive the Born rule from a more fundamental principle; but so far none of them has been successful, although it has generated a lot of interesting things for science.
This aspect of the theory also leads us to particles that are in many states at the same time. All we can predict is probability, and before measuring with a particular result, the system being measured is in an intermediate state - a superposition state that includes all possible probabilities. But whether the system is really in multiple states or is in one unknown depends on whether you prefer an ontic or epistemic model. Both of them lead us to the next point.
Quantum physics is non-local
The latter was not widely accepted as such, mainly because he was wrong. In a 1935 paper, along with his young colleagues Boris Podolkiy and Nathan Rosen (the EPR paper), Einstein made a clear mathematical statement of something that had been troubling him for some time, what we call "entanglement."
EPR's work claimed that quantum physics recognized the existence of systems in which measurements made at widely separated locations could be correlated so that the outcome of one determined the other. They argued that this meant that the results of the measurements had to be determined in advance, by some common factor, since otherwise it would be necessary to transmit the result of one measurement to the place where another was made at a speed exceeding the speed of light. Therefore, quantum physics must be incomplete, an approximation of a deeper theory (the “hidden local variable” theory, in which the results of individual measurements do not depend on something that is farther from the measurement site than a signal traveling at the speed of light can cover (locally), but rather is determined by some factor common to both systems in an entangled pair (hidden variable).
The whole thing was considered an incomprehensible footnote for more than 30 years, since there seemed to be no way to verify it, but in the mid-60s, the Irish physicist John Bell worked out the consequences of EPR in more detail. Bell showed that you can find circumstances under which quantum mechanics will predict correlations between remote measurements that are stronger than any possible theory like those proposed by E, P, and R. This was experimentally tested in the 70s by John Kloser and Alain Aspect in the early 80s. x - they showed that these intricate systems could not potentially be explained by any local hidden variable theory.
The most common approach to understanding this result is to assume that quantum mechanics is non-local: that the results of measurements made at a particular location can depend on the properties of a distant object in a way that cannot be explained using signals traveling at the speed of light. This, however, does not allow information to be transmitted at superluminal speed, although many attempts have been made to circumvent this limitation using quantum nonlocality.
Quantum physics is (almost always) concerned with the very small
Quantum physics has a reputation for being weird because its predictions are drastically different from our everyday experience. This is because its effects are less pronounced the larger the object - you will hardly see the wave behavior of the particles and how the wavelength decreases with increasing momentum. The wavelength of a macroscopic object like a walking dog is so ridiculously small that if you magnified every atom in a room to solar system, the wavelength of a dog would be the size of one atom in such a solar system.
This means that quantum phenomena are mostly limited to the scale of atoms and fundamental particles, whose masses and accelerations are small enough that the wavelength remains so small that it cannot be observed directly. However, a lot of efforts are being made to increase the size of a system that exhibits quantum effects.
Quantum physics is not magic
The previous point brings us to this quite naturally: however strange quantum physics may seem, it is clearly not magic. What it postulates is strange by the standards of everyday physics, but it is severely constrained by well-understood mathematical rules and principles.
So if someone comes to you with a "quantum" idea that seems impossible - infinite energy, magical healing power, impossible cosmic engines - it's almost certainly impossible. This doesn't mean that we can't use quantum physics to do incredible things: we are constantly writing about incredible breakthroughs using quantum phenomena, and they have already quite surprised humanity, it only means that we will not go beyond the laws of thermodynamics and common sense .
If the above points are not enough for you, consider this only a useful starting point for further discussion.