Quantum mechanics (QM -- also known as quantum physics, or quantum theory) is a branch of physics which deals with physical phenomena at nanoscopic scales where the action is on the order of the Planck constant. It departs from classical mechanics primarily at the quantum realm of atomic and subatomic length scales. Quantum mechanics provides a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. Quantum mechanics provides a substantially useful framework for many features of the modern periodic table of elements including the behavior of atoms during chemical bonding and has played a significant role in the development of many modern technologies.
In advanced topics of quantum mechanics, some of these behaviors are macroscopic (see macroscopic quantum phenomena) and emerge at only extreme (i.e., very low or very high) energies or temperatures (such as in the use of superconducting magnets). For example, the angular momentum of an electron bound to an atom or molecule is quantized.
In contrast, the angular momentum of an unbound electron is not quantized. In the context of quantum mechanics, the wave--particle duality of energy and matter and the uncertainty principle provide a unified view of the behavior of photons, electrons, and other atomic-scale objects.
The mathematical formulations of quantum mechanics are abstract. A mathematical function, the wavefunction, provides information about the probability amplitude of position, momentum, and other physical properties of a particle. Mathematical manipulations of the wavefunction usually involve bra--ket notation which requires an understanding of complex numbers and linear functionals. The wavefunction formulation treats the particle as a quantum harmonic oscillator, and the mathematics is akin to that describing acoustic resonance. Many of the results of quantum mechanics are not easily visualized in terms of classical mechanics. For instance, in a quantum mechanical model the lowest energy state of a system, the ground state, is non-zero as opposed to a more "traditional" ground state with zero kinetic energy (all particles at rest). Instead of a traditional static, unchanging zero energy state, quantum mechanics allows for far more dynamic, chaotic possibilities, according to John Wheeler.
The earliest versions of quantum mechanics were formulated in the first decade of the 20th century. About this time, the atomic theory and the corpuscular theory of light (as updated by Einstein)[1] first came to be widely accepted as scientific fact; these latter theories can be viewed as quantum theories of matter and electromagnetic radiation, respectively. Early quantum theory was significantly reformulated in the mid-1920s by Werner Heisenberg, Max Born and Pascual Jordan, (matrix mechanics); Louis de Broglie and Erwin Schrödinger (wave mechanics); and Wolfgang Pauli and Satyendra Nath Bose (statistics of subatomic particles). Moreover, the Copenhagen interpretation of Niels Bohr became widely accepted. By 1930, quantum mechanics had been further unified and formalized by the work of David Hilbert, Paul Dirac and John von Neumann[2] with a greater emphasis placed on measurement in quantum mechanics, the statistical nature of our knowledge of reality, and philosophical speculation about the role of the observer.
Quantum mechanics has since permeated throughout many aspects of 20th-century physics and other disciplines including quantum chemistry, quantum electronics, quantum optics, and quantum information science. Much 19th-century physics has been re-evaluated as the "classical limit" of quantum mechanics and its more advanced developments in terms of quantum field theory, string theory, and speculative quantum gravity theories. https://www.youtube.com/watch?v=ZsVGu...
QUANTUM FIELDS
A quantum field can be thought of as a collection of particles that are constantly interacting with one another, similar to how atoms make up a gas. Imagine a room full of people constantly bouncing around and interacting with one another. Each person represents a particle in the quantum field. Just as the temperature and pressure of the gas can change, the properties of the particles in a quantum field can also change. Additionally, just as particles in a gas can be thought of as both a wave and a particle, particles in a quantum field can also exhibit both wave-like and particle-like behavior.
According to our best theories of physics, the fundamental building blocks of matter are not particles, but continuous fluid-like substances known as 'quantum fields'. David Tong explains what we know about these fields, and how they fit into our understanding of the Universe.
MORE ON QUANTUM ENTANGLEMENT
Quantum entanglement is a phenomenon where two subatomic particles become "entangled," meaning that their properties are linked and cannot be described independently of each other. Even if the particles are separated by vast distances, a measurement on one particle will instantaneously affect the state of the other. In a way, entangled particles behave as if they are aware of how the other particle is behaving.
One way to explain this is to imagine two dice that are connected by a rubber band. When you roll one die, the other die will automatically roll to the same number. Even if the dice are separated by a great distance, the number on one die will always match the number on the other die. This is similar to how entangled particles are connected; even when separated by large distances, their properties will always match.
Another analogy is a pair of gloves that are connected by a string. The glove on the left hand and the one on the right hand are separate objects but are connected by the string. If you stretch the left glove's fingers, the one on the right will also stretch, no matter how far they are apart.
PHYSICIST SEAN CARROLL EXPLAINS QUANTUM PHYSICS & PARALLEL UNIVERSES
The idea of parallel universes, also known as the "many-worlds" interpretation of quantum mechanics, is a way to explain this phenomenon. According to this interpretation, when a particle is in a state of superposition, the universe splits into multiple versions, or "parallel universes," each with a different outcome. In one universe, the particle may be in one state, while in another universe it could be in a different state. In this way, every possible outcome of a quantum event is said to occur in a separate universe.
QUTOES ON QUANTUM MECHANICS
“In the world of the very small, where particle and wave aspects of reality are equally significant, things do not behave in any way that we can understand from our experience of the everyday world...all pictures are false, and there is no physical analogy we can make to understand what goes on inside atoms. Atoms behave like atoms, nothing else.”
― John Gribbin, In Search of Schrödinger's Cat: Quantum Physics and Reality
“As far as quantum field theory is concerned, a human being or the center of a star isn’t all that different from empty space.”
― Sean Carroll, Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime
“Particles are constantly winking in and out of existence, like tiny Cheshire cats.”
― Charles Seife, Zero: The Biography of a Dangerous Idea
“Quantum physics resembles the deep 'code layer' underlying our physical reality.”
― Alex M. Vikoulov, The Syntellect Hypothesis: Five Paradigms of the Mind's Evolution
“Theology, philosophy, metaphysics, and quantum physics are merely ways for God to have his smart people believe in him”
― Jeremy Aldana
“Quantum reality is not constrained to the realm of ultra-small. In a certain sense, we are all quantum wavicles meaning that a version of you can wildly vary from one observer to another. That's where I’ve come to realize that observer systemic alternate timelines are true parallel universes.”
― Alex M. Vikoulov, The Syntellect Hypothesis: Five Paradigms of the Mind's Evolution
“Quantum physics tells us that no matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities.
The universe, according to quantum physics, has no single past, or history. The fact that the past takes no definite form means that observations you make on a system in the present affect its past.”
― Stephen Hawking, The Grand Design
“Where misunderstanding dwells, misuse will not be far behind. No theory in the history of science has been more misused and abused by cranks and charlatans—and misunderstood by people struggling in good faith with difficult ideas—than quantum mechanics.”
― Sean Carroll, The Big Picture: On the Origins of Life, Meaning, and the Universe Itself
“The more we delve into quantum mechanics the stranger the world becomes; appreciating this strangeness of the world, whilst still operating in that which you now consider reality, will be the foundation for shifting the current trajectory of your life from ordinary to extraordinary. It is the Tao of mixing this cosmic weirdness with the practical and physical, which will allow you to move, moment by moment, through parallel worlds to achieve your dreams.”
― Kevin Michel, Moving Through Parallel Worlds To Achieve Your Dreams
“In modern physics, there is no such thing as "nothing." Even in a perfect vacuum, pairs of virtual particles are constantly being created and destroyed. The existence of these particles is no mathematical fiction. Though they cannot be directly observed, the effects they create are quite real. The assumption that they exist leads to predictions that have been confirmed by experiment to a high degree of accuracy.”
― Richard Morris
“[On the practical applications of particle physics research with the Large Hadron Collider.]
Sometimes the public says, 'What's in it for Numero Uno? Am I going to get better television reception? Am I going to get better Internet reception?' Well, in some sense, yeah. ... All the wonders of quantum physics were learned basically from looking at atom-smasher technology. ... But let me let you in on a secret: We physicists are not driven to do this because of better color television. ... That's a spin-off. We do this because we want to understand our role and our place in the universe.”
― Michio Kaku
“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”
― Albert Einstein
“Quantum Mechanics doesn't deserve the connotation of spookiness in the sense of some ineffable mystery that it is beyond the human mind to comprehend. Quantum Mechanics is amazing; it is novel, profound, mind-stretching & a very different view of reality from what we’re used to.”
― Sean Carroll, Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime
"It from bit symbolizes the idea that every item of the physical world has at bottom—a very deep bottom, in most instances—an immaterial source and explanation; that which we call reality arises in the last analysis from the posing of yes-or-no questions and the registering of equipment-evoked responses; in short, that all things physical are information-theoretic in origin and that this is a participatory universe." - John Archibald Wheeler
A Look at Quantum Biology: Let There Be Life
Professor Jim Al-Khalili traces the story of arguably the most important, accurate and yet perplexing scientific theory ever: quantum physics.
The Secrets Of Quantum Physics (Jim Al-Khalili) | Spark
Professor Jim Al-Khalili traces the story of arguably the most important, accurate and yet perplexing scientific theory ever: quantum physics.
Brian Randolph Greene is an American theoretical physicist, mathematician, and string theorist. He has been a professor at Columbia University since 1996 and chairman of the World Science Festival since co-founding it in 2008.