While quantum mechanics primarily applies to the smaller atomic regimes of matter and energy, some systems exhibit quantum mechanical effects on a large scale. Superfluidity, the frictionless flow of a liquid at …start, in Chapter 3, by examining how many of the central ideas of quantum mechanics are a direct consequence of wave-particle duality—i.e., the concept that waves sometimes act as particles, and particles as waves. We shall then proceed to investigate the rules of quantum mechanics in a more systematic fashion in Chapter 4. Quantum mechanics isIn quantum mechanics, the probability current (sometimes called probability flux) is a mathematical quantity describing the flow of probability.Specifically, if one thinks of probability as a heterogeneous fluid, then the probability current is the rate of flow of this fluid. It is a real vector that changes with space and time. Probability currents are …There are 3 modules in this course. Course 2 of Statistical Thermodynamics presents an introduction to quantum mechanics at a level appropriate for those with mechanical or aerospace engineering backgrounds. Using a postulatory approach that describes the steps to follow, the Schrodinger wave equation is derived and simple solutions obtained ... Quantum physics deals with the foundation of our world – the electrons in an atom, the protons inside the nucleus, the quarks that build those protons, and t... 9. 10. Best Bakeries in Al Qaţīf, Eastern Province, Saudi Arabia. Alyahya Bakeries مخابز اليحيى, Harat Rahhal Bakery, Abu Saud Bakeries and Sweets, Rageef Tarout Bakery, Al-Sultan …The original interpretation of quantum mechanics was mainly put forward by Niels Bohr, and is called the Copenhagen interpretation. Broadly speaking, it says that the quantum state is a convenient fiction, used to calculate the results of measurement outcomes, and that the system cannot be considered separate from the measurement apparatus.The index n n is called the energy quantum number or principal quantum number. The state for n = 2 n = 2 is the first excited state, the state for n = 3 n = 3 is the second excited state, and so on. The first three quantum states (for n = 1, 2, and 3) of a particle in a box are shown in Figure 4.5.2 4.5. 2.Quantum physics deals with the foundation of our world – the electrons in an atom, the protons inside the nucleus, the quarks that build those protons, and t... Course Description. Together, this course and 8.06 Quantum Physics III cover quantum physics with applications drawn from modern physics. Topics covered in this course include the general formalism of quantum mechanics, harmonic oscillator, quantum mechanics in three-dimensions, angular momentum, spin, and addition of angular momentum. …. Quantum mechanics was once mostly of interest to physicists, chemists and other basic scientists. Now the concepts and techniques of quantum mechanics are essential in many areas of engineering and science such as materials science, nanotechnology, electronic devices, and photonics. This course is a substantial introduction to quantum mechanics ... There’s quantum mechanics, the basic mathematical framework that underpins it all, which was first developed in the 1920s by Niels Bohr, Werner Heisenberg, Erwin Schrödinger and others. It ... of his research is in electrodynamics and quantum mechanics. He is the author of over fty arti-cles and four books: Introduction to Electrodynamics (4th edition, Cambridge University Press, 2013), Introduction to Elementary Particles (2nd edition, Wiley-VCH, 2008), Introduction to Quantum Mechanics (2nd edition, Cambridge, 2005), and 1. Key Features of Quantum Mechanics: Linearity of the Equations of Motion, Complex Numbers are Essential, Loss of Determinism, Quantum Superpositions, Entanglement (PDF) 2. Experiments with Photons: Mach-Zehder Interferometer, Elitzur-Vaidman Bombs (PDF) 3. Particle Nature of Light and Wave Nature of Matter: Photoelectric Effect, Compton ... Postulate 3. For every observable property of a system there is a quantum mechanical operator. The operator for position of a particle in three dimensions is just the set of coordinates x x, y y, and z z, which is written as a vector. The operator for a component of momentum is. P^x = −iℏ ∂ ∂x (3.9.4) (3.9.4) P ^ x = − i ℏ ∂ ∂ x.Course Description. This course covers the experimental basis of quantum physics. It introduces wave mechanics, Schrödinger’s equation in a single dimension, and Schrödinger’s equation in three dimensions. It is the first course in the undergraduate Quantum Physics sequence, followed by 8.05 Quantum Physics II and 8.06 Quantum ….Mathematically, quantum mechanics can be regarded as a non-classical probability calculus resting upon a non-classical propositional logic. More specifically, in quantum mechanics each probability-bearing proposition of the form “the value of physical quantity \(A\) lies in the range \(B\)” is represented by a projection operator on a Hilbert …Instead, classical mechanics is now considered an approximate theory to the more general quantum mechanics. Emphasis has shifted to understanding the fundamental forces of nature as in the Standard Model and its more modern extensions into a unified theory of everything. Classical mechanics is a theory useful for the study of the motion … This is the first semester of a two-semester graduate-level subject on quantum theory, stressing principles. Quantum theory explains the nature and behavior of matter and energy on the atomic and subatomic level. Topics include Fundamental Concepts, Quantum Dynamics, Composite Systems, Symmetries in Quantum Mechanics, and Approximation Methods. Quantum computing uses specialized technology—including computer hardware and algorithms that take advantage of quantum mechanics—to solve complex problems that classical computers or supercomputers can’t solve, or can’t solve quickly enough. Today, IBM Quantum makes real quantum hardware—a tool that scientists only began to … quantum mechanics, Branch of mathematical physics that deals with atomic and subatomic systems. It is concerned with phenomena that are so small-scale that they cannot be described in classical terms, and it is formulated entirely in terms of statistical probabilities. Considered one of the great ideas of the 20th century, quantum mechanics was ... Modern Quantum Mechanics is a classic graduate level textbook, covering the main quantum mechanics concepts in a clear, organized and engaging manner. The author, Jun John Sakurai, was a renowned theorist in particle theory. The second edition, revised by Jim Napolitano, introduces topics that extend the text's usefulness into the twenty-first ...Current Weather. 8:54 PM. 71° F. RealFeel® 67°. Air Quality Unhealthy. Wind WNW 12 mph. Wind Gusts 13 mph. Partly cloudy More Details. An interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Although quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily broad range of experiments, there exist a number of contending schools of thought over ... In his estimation, quantum mechanics is a broad-brush theory that expresses the overall behavior of nature’s building blocks but lacks the resolution to capture individual cases. A deeper, more ...View full lesson: http://ed.ted.com/lessons/particles-and-waves-the-central-mystery-of-quantum-mechanics-chad-orzelOne of the most amazing facts in physics i... Quantum physics deals with the foundation of our world – the electrons in an atom, the protons inside the nucleus, the quarks that build those protons, and t... Becker questions the hegemony of the Copenhagen interpretation of quantum mechanics. Propounded by Bohr and Werner Heisenberg in the 1920s, this theory holds that physical systems have only ...Quantum mechanics describes how these particles interact with each other and with light, X-rays, gamma rays, and other forms of electromagnetic radiation. One of the great ideas of the 20th century, quantum mechanics continues to be at the forefront of advances in physics in the 21st century. In addition to explaining the structure of atoms and ... Quantum mechanics - Heisenberg, Uncertainty, Principle: The observables discussed so far have had discrete sets of experimental values. For example, the values of the energy of a bound system are always discrete, and angular momentum components have values that take the form mℏ, where m is either an integer or a half-integer, positive or negative. On the other hand, the position of a ... In this quantum physics introduction for beginners, we will explain quantum physics, also called quantum mechanics, in simple terms. Quantum physics is possibly the most fascinating part of physics that exists. It is the amazing physics that becomes relevant for small particles, where the so-called classical physics is no longer valid.Quantum mechanics of time travel. Until recently, most studies on time travel have been based upon classical general relativity. Coming up with a quantum version of time travel requires physicists to figure out the time evolution equations for density states in the presence of closed timelike curves (CTC). Novikov [1] had conjectured that once ...Quantum mechanics. Quantum chaos is the field of physics attempting to bridge the theories of quantum mechanics and classical mechanics. The figure shows the main ideas running in each direction. Quantum chaos is a branch of physics which studies how chaotic classical dynamical systems can be described in terms of quantum theory.This 9 week course aims to teach quantum mechanics to anyone with a reasonable college-level understanding of physical science or engineering. Quantum mechanics was once mostly of interest to physicists, chemists and other basic scientists. Now the concepts and techniques of quantum mechanics are essential in many areas of engineering and ... Quantum Mechanics. In day to day life, we intuitively understand how the world works. Drop a glass and it will smash to the floor. Push a wagon and it will roll along. Walk to a wall and you can't ... MIT 8.04 Quantum Physics I, Spring 2013View the complete course: http://ocw.mit.edu/8-04S13Instructor: Allan AdamsIn this lecture, Prof. Adams discusses a se...That theory is known as quantum mechanics, and it is now the basic framework for understanding atomic, nuclear, and subnuclear physics, as well as condensed-matter (or ”solid-state”) physics. The laws of motion (due to Galileo, Newton,...) which preceded quantum theory are referred to as classical mechanics.Apr 11, 2024 · Although quantum mechanics is essential to understand microscopic systems, it has little effect on heavier objects. Experiments have now put strict constraints on theories that use gravity to ... Unlike a classical oscillator, the measured energies of a quantum oscillator can have only energy values given by Equation 7.6.6. Moreover, unlike the case for a quantum particle in a box, the allowable energy levels are evenly spaced, ΔE = En + 1 − En = 2(n + 1) + 1 2 ℏω − 2n + 1 2 ℏω = ℏω = hf.At the end of this course learners will be able to: 1. demonstrate full grasp of basic concepts in quantum mechanics including wave-particle duality, operators and wavefunctions, and evolution of quantum states, 2. achieve mastery of the mathematical apparatus needed for quantum mechanics and 3. attain foundational knowledge required to learn ...Quantum mechanics is a set of principles underlying the most fundamental known description of all physical systems at the submicroscopic scale (at the atomic level). Notable among these principles ...This 9 week course aims to teach quantum mechanics to anyone with a reasonable college-level understanding of physical science or engineering. Quantum mechanics was once mostly of interest to physicists, chemists and other basic scientists. Now the concepts and techniques of quantum mechanics are essential in many areas of engineering and ...Quantum mechanics describes how these particles interact with each other and with light, X-rays, gamma rays, and other forms of electromagnetic radiation. One of the great ideas of the 20th century, quantum mechanics continues to be at the forefront of advances in physics in the 21st century. In addition to explaining the structure of atoms and ...Quantum mechanics: How the future might influence the past. In 2022, the Physics Nobel prize was awarded for experimental work showing that the quantum world must break some of our fundamental ...Learn about the history, formalism and applications of quantum mechanics, a branch of physics that describes physical systems with discrete properties and wave-particle duality. Explore examples, … Physics - Quantum Mechanics, Particles, Waves: Although the various branches of physics differ in their experimental methods and theoretical approaches, certain general principles apply to all of them. The forefront of contemporary advances in physics lies in the submicroscopic regime, whether it be in atomic, nuclear, condensed-matter, plasma, or particle physics, or in quantum optics, or ... The quantum mechanical model of the atom (Opens a modal) Heisenberg uncertainty principle (Opens a modal) Quantum numbers (Opens a modal) Quantum numbers for the first four shells (Opens a modal) Nuclei. Learn. Mass defect and binding energy (Opens a modal) Nuclear stability and nuclear equationsAn interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Although quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily broad range of experiments, there exist a number of contending schools of thought over ... This 9 week course aims to teach quantum mechanics to anyone with a reasonable college-level understanding of physical science or engineering. Quantum mechanics was once mostly of interest to physicists, chemists and other basic scientists. Now the concepts and techniques of quantum mechanics are essential in many areas of engineering and ... Quantum Mechanics is a set of mathematical rules upon which physical theories are constructed. Applying the rules of quantum mechanics, it is possible to calculate the observables of an isolated physical system, at any instant in …1.2 Quantum Mechanics, what’s up? As a warmup, some quick questions and answers about Quantum Mechanics... Why would I learn Quantum mechanics? Let’s think a bit about the physics you have learned so far. Throughout the past years, you got to know how bodies experience and exert forces, how gases behave, how electro-magnetic forces act …Lewis presents quantum mechanics as a theory of matrix mechanics and then, in the continuum limit, as a theory of wave mechanics. He gives a clear visual explanation of the use of different bases for spin, which nicely sets up the proof of Bell's theorem in chapter 2. All of this is done without requiring the reader to multiply matrices …In quantum mechanics, the probability current (sometimes called probability flux) is a mathematical quantity describing the flow of probability.Specifically, if one thinks of probability as a heterogeneous fluid, then the probability current is the rate of flow of this fluid. It is a real vector that changes with space and time. Probability currents are …quantum computing, and closes with a discussion of the still unresolved prob-lem of measurement. Chapter 6 also demonstrates that thermodynamics is a straightforward consequence of quantum mechanics and that we no longer need to derive the laws of thermodynamics through the traditional, rather subtle, arguments about heat engines.This textbook, now in an expanded third edition, emphasizes the importance of advanced quantum mechanics for materials science and all experimental techniques which employ photon absorption, emission, or scattering. Important aspects of introductory quantum mechanics are covered in the first seven chapters to make the subject self-contained …Lewis presents quantum mechanics as a theory of matrix mechanics and then, in the continuum limit, as a theory of wave mechanics. He gives a clear visual explanation of the use of different bases for spin, which nicely sets up the proof of Bell's theorem in chapter 2. All of this is done without requiring the reader to multiply matrices …Quantum physics deals with the foundation of our world – the electrons in an atom, the protons inside the nucleus, the quarks that build those protons, and t...Quantum mechanics describes how these particles interact with each other and with light, X-rays, gamma rays, and other forms of electromagnetic radiation. One of the great ideas of the 20th century, quantum mechanics continues to be at the forefront of advances in physics in the 21st century. In addition to explaining the structure of atoms and ...Nov 19, 2023 · Quantum mechanics is an essential branch of physics that explains the properties and behaviors of particles at the atomic and subatomic scale. It challenges the principles of classical mechanics with concepts like quantization, where properties like energy exist in discrete units, and wave-particle duality, where particles exhibit both particle ... These special wavefunctions are called eigenstates, and the multiples are called eigenvalues. Thus, if. Aψa(x) = aψa(x), (3.8.1) (3.8.1) A ψ a ( x) = a ψ a ( x), where a a is a complex number, then ψa ψ a is called an eigenstate of A A corresponding to the eigenvalue a a. Suppose that A A is an Hermitian operator corresponding to some ...Quantum mechanics is an essential branch of physics that explains the properties and behaviors of particles at the atomic and subatomic scale. It challenges the principles of classical mechanics with concepts like quantization, where properties like energy exist in discrete units, and wave-particle duality, where particles exhibit both …Explain how quantum tunneling is utilized in modern technologies. Quantum tunneling is a phenomenon in which particles penetrate a potential energy barrier with a height greater than the total energy of the particles. The phenomenon is interesting and important because it violates the principles of classical mechanics. A fundamental concept in quantum mechanics is that of randomness, or indeterminacy. In general, the theory predicts only the probability of a certain result. Consider the case of radioactivity. Imagine a box of atoms with identical nuclei that can undergo decay with the emission of an alpha particle. In a given time interval, a certain fraction ... In this quantum physics introduction for beginners, we will explain quantum physics, also called quantum mechanics, in simple terms. Quantum physics is possibly the most fascinating part of physics that exists. It is the amazing physics that becomes relevant for small particles, where the so-called classical physics is no longer valid.Quantum Mechanics Concepts and Applications Second Edition Nouredine Zettili Jacksonville State University, Jacksonville, USA A John Wiley and Sons, Ltd., PublicationIn quantum mechanics with complex numbers, the particles Alice and Charlie receive don’t need to be entangled with each other. No real-number description, however, can replicate the pattern of correlations that the three physicists will measure. The new paper shows that treating the system as real requires introducing extra information that ...The phase-space formulation of quantum mechanics places the position and momentum variables on equal footing in phase space. In contrast, the Schrödinger picture uses the position or momentum representations (see also position and momentum space ). The two key features of the phase-space formulation are that the quantum state is described …This textbook, now in an expanded third edition, emphasizes the importance of advanced quantum mechanics for materials science and all experimental techniques which employ photon absorption, emission, or scattering. Important aspects of introductory quantum mechanics are covered in the first seven chapters to make the subject self-contained …In quantum mechanics, the variational method is one way of finding approximations to the lowest energy eigenstate or ground state, and some excited states.This allows calculating approximate wavefunctions such as molecular orbitals. The basis for this method is the variational principle.. The method consists of choosing a "trial wavefunction" depending … 1–1 Atomic mechanics. “Quantum mechanics” is the description of the behavior of matter and light in all its details and, in particular, of the happenings on an atomic scale. Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do ... 1.1: Why Quantum Mechanics is Necessary; 1.2: The Schrödinger Equation and Its Components; 1.3: The Born-Oppenheimer Approximation One of the most important approximations relating to applying quantum mechanics to molecules and molecular ions is known as the Born-Oppenheimer (BO) approximation. 1.4: Free Particle Motions in More …Gravity and quantum mechanics tend to stay out of each other's way, but this might change as we devise new experiments to test the applicability of quantum theory to macroscopic systems and larger ...This is the first course in the undergraduate Quantum Physics sequence. It introduces the basic features of quantum mechanics. It covers the experimental basis of quantum …start, in Chapter 3, by examining how many of the central ideas of quantum mechanics are a direct consequence of wave-particle duality—i.e., the concept that waves sometimes act as particles, and particles as waves. We shall then proceed to investigate the rules of quantum mechanics in a more systematic fashion in Chapter 4. Quantum mechanics isquantum mechanics, Branch of mathematical physics that deals with atomic and subatomic systems. It is concerned with phenomena that are so small-scale that they cannot be described in classical terms, and it is formulated entirely in terms of statistical probabilities. Considered one of the great ideas of the 20th century, quantum …Quantum mechanics is the best tool we have to understand how the universe works on its smallest scales. Everything we can see around us, from far-off galaxies to our own bodies, is made up of... Lecture 1: An overview of quantum mechanics. Quantum mechanics as a framework. Defining linearity (17:46) Linearity and nonlinear theories. Schrödinger’s equation (10:01) The nature of superposition. Mach-Zehnder interferometer (14:30) Lecture 2: Overview of quantum mechanics (cont.). Interaction-free measurements. Quantum mechanics offers us a way to describe the atomic world to a surprising degree of precision. Its predictions often defy our intuition of the world. All of the remarkable and surprising quantum phenomena come from the fact that probability is at the heart of quantum mechanics. We can never know what will happen for sure.Nov 19, 2023 · Quantum mechanics is an essential branch of physics that explains the properties and behaviors of particles at the atomic and subatomic scale. It challenges the principles of classical mechanics with concepts like quantization, where properties like energy exist in discrete units, and wave-particle duality, where particles exhibit both particle ... Quantum is an open-access peer-reviewed journal for quantum science and related fields. Quantum is non-profit and community-run: an effort by researchers and for researchers to make science more open and publishing more transparent and efficient. Sign up for our monthly digest of papers and other news. Quantum physics is the result of applying the framework of quantum mechanics to di erent physical phenomena. We thus have Quantum Electrodynamics, when quantum mechanics is applied to electromagnetism, Quantum Optics, when it is applied to light and optical devices, or Quantum Gravity, when it is applied to gravitation. 4.8 stars. 6 ratings. Learn the fundamental notions of quantum mechanics at a level that is accessible to everyone. This course is listed as one of the best online courses of all time by Class Central and was a finalist for the 2018 edX Prize for Exceptional Contributions to Online Teaching and Learning. Play Video. 6 weeks. 7–10 hours per week. Modern Quantum Mechanics is a classic graduate level textbook, covering the main concepts from quantum mechanics in a clear, organized and engaging manner. The original author, J. J. Sakurai, was a renowned particle theorist. This third edition, revised by Jim Napolitano, introduces topics that extend its value into the twenty-first century ...Beginning with a review of the history of quantum mechanics and an account of classic solutions of the Schrödinger equation, before quantum mechanics is developed in a modern Hilbert space approach, Weinberg uses his remarkable expertise to elucidate topics such as Bloch waves and band structure, the Wigner–Eckart theorem, magic numbers ...Conclusion. In conclusion, Al Qaţīf’s architecture is a vibrant blend of past and present, a reflection of Saudi Arabia’s rich cultural heritage and its dynamic … Quantum mechanics - Heisenberg, Uncertainty, Principle: The observables discussed so far have had discrete sets of experimental values. For example, the values of the energy of a bound system are always discrete, and angular momentum components have values that take the form mℏ, where m is either an integer or a half-integer, positive or negative. On the other hand, the position of a ...
Nov 19, 2023 · Quantum mechanics is an essential branch of physics that explains the properties and behaviors of particles at the atomic and subatomic scale. It challenges the principles of classical mechanics with concepts like quantization, where properties like energy exist in discrete units, and wave-particle duality, where particles exhibit both particle ... . Openai translator
Quantum physics is sometimes called quantum mechanics or quantum field theory. It also has various subfields, as discussed above, which are sometimes used interchangeably with quantum physics, though quantum physics is actually the broader term for all of these disciplines. of his research is in electrodynamics and quantum mechanics. He is the author of over fty arti-cles and four books: Introduction to Electrodynamics (4th edition, Cambridge University Press, 2013), Introduction to Elementary Particles (2nd edition, Wiley-VCH, 2008), Introduction to Quantum Mechanics (2nd edition, Cambridge, 2005), and Quantum mechanics is a set of principles underlying the most fundamental known description of all physical systems at the submicroscopic scale (at the atomic level). Notable among these principles ... 1.1: Why Quantum Mechanics is Necessary; 1.2: The Schrödinger Equation and Its Components; 1.3: The Born-Oppenheimer Approximation One of the most important approximations relating to applying quantum mechanics to molecules and molecular ions is known as the Born-Oppenheimer (BO) approximation. 1.4: Free Particle Motions in More …Quantum Mechanix Inc. is a creative studio and developer of screen-accurate collectibles and digital apps and games inspired by popular movies and TV shows. 0% Complete Quantum MechanixThis is a superposition of waves. Similarly, in quantum science, objects such as electrons and photons have wavelike properties that can combine and become what is called superposed. While waves on the surface of a pond are formed by the movement of water, quantum waves are mathematical. They are expressed as equations that describe the ...Canonical commutation rule for position q and momentum p variables of a particle, 1927.pq − qp = h/(2πi).Uncertainty principle of Heisenberg, 1927. The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics.It states that there is a limit to the precision with which certain pairs of …Quantum Mechanics. Four basic principles of quantum mechanics are: (3.1) Physical States. Every physical system is associated with a Hilbert Space, every unit vector in the space corresponds to a …Quantum mechanics is the branch of physics that deals with the behavior of matter and light on a subatomic and atomic level. It …quantum mechanics, Branch of mathematical physics that deals with atomic and subatomic systems. It is concerned with phenomena that are so small-scale that they cannot be described in classical terms, and it is formulated entirely in terms of statistical probabilities. Considered one of the great ideas of the 20th century, quantum …May 12, 2015 · Leonard Susskind is the Felix Bloch Professor in Theoretical Physics at Stanford University. He is the author of Quantum Mechanics (with Art Friedman) and The Theoretical Minimum (with George Hrabovsky), among other books. He lives in Palo Alto, California. Art Friedman is a data consultant who previously spent fifteen years at Hewlett-Packard ... That theory is known as quantum mechanics, and it is now the basic framework for understanding atomic, nuclear, and subnuclear physics, as well as condensed-matter (or ”solid-state”) physics. The laws of motion (due to Galileo, Newton,...) which preceded quantum theory are referred to as classical mechanics. 4.8 stars. 6 ratings. Learn the fundamental notions of quantum mechanics at a level that is accessible to everyone. This course is listed as one of the best online courses of all time by Class Central and was a finalist for the 2018 edX Prize for Exceptional Contributions to Online Teaching and Learning. Play Video. 6 weeks. 7–10 hours per week. The history of quantum mechanics is a fundamental part of the history of modern physics. The major chapters of this history begin with the emergence of quantum ideas to explain individual phenomena—blackbody radiation, the photoelectric effect, solar emission spectra—an era called the Old or Older quantum theories. [1]start, in Chapter 3, by examining how many of the central ideas of quantum mechanics are a direct consequence of wave-particle duality—i.e., the concept that waves sometimes act as particles, and particles as waves. We shall then proceed to investigate the rules of quantum mechanics in a more systematic fashion in Chapter 4. Quantum mechanics isQuantum 101. What is quantum? Quantum mechanics is the physics of the very small. It explains and predicts the behaviour of atoms and molecules in a way that redefines our understanding of nature. It is the most precise description that we have of the world, and yet, it predicts surprising, often counter-intuitive behaviours..