Q U A N T U M T H E O R Y
"Quantum theory is the crowning intellectual achievement of the last century. It's the underlying principle
for many of today's devices, from lasers to magnetic resonance imaging machines. And these may prove to be just the low-hanging fruit. Many scientists foresee revolutionary technologies based on the truly strange properties
of the quantum world.”
JOHN PRESKILL - California Institute of Technology
for many of today's devices, from lasers to magnetic resonance imaging machines. And these may prove to be just the low-hanging fruit. Many scientists foresee revolutionary technologies based on the truly strange properties
of the quantum world.”
JOHN PRESKILL - California Institute of Technology
The Enigma in a Nutshell
Quantum mechanics is the most battle-tested theory in all of science. It is also practical. (One third of our economy depends on things designed with it.) But, with the advent of quantum mechanics, physicists, unexpectedly, felt the need to talk of reality, connectedness–and even, though with some hesitancy, “consciousness.”
Reality: Undisputed experimental results challenge any common-sense view of physical reality. By your free choice you can establish either of two contradictory prior physical realities. What existed before your observation? Experts in the foundations of quantum mechanics still puzzle about and argue about this.
While the creation of physical reality can be demonstrated only for small things, like molecules, or “simple” situations, only technology sets the limit. Quantum theory is seamless. Cosmologists apply quantum mechanics to black holes and the Big Bang.
Quantum mechanics is the most battle-tested theory in all of science. It is also practical. (One third of our economy depends on things designed with it.) But, with the advent of quantum mechanics, physicists, unexpectedly, felt the need to talk of reality, connectedness–and even, though with some hesitancy, “consciousness.”
Reality: Undisputed experimental results challenge any common-sense view of physical reality. By your free choice you can establish either of two contradictory prior physical realities. What existed before your observation? Experts in the foundations of quantum mechanics still puzzle about and argue about this.
While the creation of physical reality can be demonstrated only for small things, like molecules, or “simple” situations, only technology sets the limit. Quantum theory is seamless. Cosmologists apply quantum mechanics to black holes and the Big Bang.
If we are still going to put up with these damn quantum jumps, I am sorry that I ever had anything
to do with quantum theory.”
Erwin Schrödinger
to do with quantum theory.”
Erwin Schrödinger
Quantum theory tells that all things that have ever interacted are forever connected. For example, your friend’s freely made decision of what to do in Moscow (or on Mars) can instantaneously influence what you find in Manhattan. And this happens without any physical force being involved. Einstein called such influences “spooky actions.” They have now been demonstrated to exist. So far just for small things, but they are no less spooky.
These two quantum phenomena are technically called “wavefunction collapse” and “entanglement.” They are NOT hard to understand–even with zero physics background. But they are almost impossible to believe. When someone tells you something you can’t believe, you might well think you don’t understand. But believing might be the real problem. It’s best to approach the subject with an open mind. This is not easy.
The facts described in our book are completely undisputed. But mentioning “consciousness” is controversial. The encounter of physics with “non-physical” stuff like consciousness has been called our “skeleton in the closet.” Look at the undisputed facts, and think for yourself about what they mean.
These two quantum phenomena are technically called “wavefunction collapse” and “entanglement.” They are NOT hard to understand–even with zero physics background. But they are almost impossible to believe. When someone tells you something you can’t believe, you might well think you don’t understand. But believing might be the real problem. It’s best to approach the subject with an open mind. This is not easy.
The facts described in our book are completely undisputed. But mentioning “consciousness” is controversial. The encounter of physics with “non-physical” stuff like consciousness has been called our “skeleton in the closet.” Look at the undisputed facts, and think for yourself about what they mean.
"Anyone not shocked by quantum mechanics has not yet understood it."
NIELS BOHR
NIELS BOHR
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of the dual particle-like and wave-like behavior and interaction of matter and energy. The theory was discovered in 1925 by Werner Heisenberg.[1] Heisenberg was awarded the Nobel Prize in physics 1932 for this seminal achievement.[2]Quantum mechanics describes the time evolution of physical systems via a mathematical structure called the wave function. The wave function encapsulates the probability that the system is to be found in a given state at a given time. Quantum mechanics also allows one to calculate the effect on the system of making measurements of properties of the system by defining the effect of those measurements on the wave function. This leads to the well-known uncertainty principle as well as the enduring debate over the role of the experimenter, epitomised in theSchrödinger's Cat thought experiment.
Quantum mechanics differs significantly from classical mechanics in its predictions when the scale of observations becomes comparable to the atomic and sub-atomic scale, the so-calledquantum realm. However, many macroscopic properties of systems can only be fully understood and explained with the use of quantum mechanics. Phenomena such as superconductivity, the properties of materials such as semiconductors and nuclear and chemical reaction mechanisms observed as macroscopic behaviour, cannot be explained using classical mechanics.
The term was coined by Max Planck, and derives from the observation that some physical quantities can be changed only by discrete amounts, or quanta, as multiples of the Planck constant, rather than being capable of varying continuously or by any arbitrary amount. For example, the angular momentum, or more generally the action,[citation needed] of an electron bound into an atom or molecule is quantized. Although an unbound electron does not exhibit quantized energy levels, one which is bound in an atomic orbital has quantized values of angular momentum. 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. Similarly, the implications are often counter-intuitive in terms of classical physics. The centerpiece of the mathematical formulation is the wavefunction (defined by Schrödinger's wave equation), which describes the probability amplitude of the position and momentum of a particle. Mathematical manipulations of the wavefunction usually involve the bra-ket notation, which requires an understanding of complex numbers and linear functionals. The wavefunction treats the object as a quantum harmonic oscillator and the mathematics is akin to that of acoustic resonance.
Many of the results of quantum mechanics do not have models that are easily visualized in terms of classical mechanics; for instance, the ground state in the quantum mechanical model is a non-zero energy state that is the lowest permitted energy state of a system, rather than a traditional classical system that is thought of as simply being at rest with zero kinetic energy.
Quantum mechanics differs significantly from classical mechanics in its predictions when the scale of observations becomes comparable to the atomic and sub-atomic scale, the so-calledquantum realm. However, many macroscopic properties of systems can only be fully understood and explained with the use of quantum mechanics. Phenomena such as superconductivity, the properties of materials such as semiconductors and nuclear and chemical reaction mechanisms observed as macroscopic behaviour, cannot be explained using classical mechanics.
The term was coined by Max Planck, and derives from the observation that some physical quantities can be changed only by discrete amounts, or quanta, as multiples of the Planck constant, rather than being capable of varying continuously or by any arbitrary amount. For example, the angular momentum, or more generally the action,[citation needed] of an electron bound into an atom or molecule is quantized. Although an unbound electron does not exhibit quantized energy levels, one which is bound in an atomic orbital has quantized values of angular momentum. 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. Similarly, the implications are often counter-intuitive in terms of classical physics. The centerpiece of the mathematical formulation is the wavefunction (defined by Schrödinger's wave equation), which describes the probability amplitude of the position and momentum of a particle. Mathematical manipulations of the wavefunction usually involve the bra-ket notation, which requires an understanding of complex numbers and linear functionals. The wavefunction treats the object as a quantum harmonic oscillator and the mathematics is akin to that of acoustic resonance.
Many of the results of quantum mechanics do not have models that are easily visualized in terms of classical mechanics; for instance, the ground state in the quantum mechanical model is a non-zero energy state that is the lowest permitted energy state of a system, rather than a traditional classical system that is thought of as simply being at rest with zero kinetic energy.
“When I hear about Schrödinger’s cat, I reach for my gun.”
STEPHEN HAWKING
STEPHEN HAWKING
Fundamentally, it attempts to explain the peculiar behaviour of matter and energy at the subatomic level—an attempt which has produced more accurate results than classical physics in predicting how individual particles behave. But many unexplained anomalies remain.
Historically, the earliest versions of quantum mechanics were formulated in the first decade of the 20th Century, around the time that atomic theory and the corpuscular theory of light as interpreted by Einstein first came to be widely accepted as scientific fact; these later theories can be viewed as quantum theories of matter and electromagnetic radiation.
Following Schrödinger's breakthrough in deriving his wave equation in the mid-1920s, quantum theory was significantly reformulated away from the old quantum theory, towards the quantum mechanics of Werner Heisenberg, Max Born, Wolfgang Pauli and their associates, becoming a science of probabilities based upon the Copenhagen interpretation of Niels Bohr. By 1930, the reformulated theory had been further unified and formalized by the work of Paul Dirac and John von Neumann, with a greater emphasis placed on measurement, the statistical nature of our knowledge of reality, and philosophical speculations about the role of the observer.
The Copenhagen interpretation quickly became (and remains) the orthodox interpretation. However, due to the absence of conclusive experimental evidence there are also many competing interpretations.
Quantum mechanics has since branched out into almost every aspect of physics, and into other disciplines such as 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.
Historically, the earliest versions of quantum mechanics were formulated in the first decade of the 20th Century, around the time that atomic theory and the corpuscular theory of light as interpreted by Einstein first came to be widely accepted as scientific fact; these later theories can be viewed as quantum theories of matter and electromagnetic radiation.
Following Schrödinger's breakthrough in deriving his wave equation in the mid-1920s, quantum theory was significantly reformulated away from the old quantum theory, towards the quantum mechanics of Werner Heisenberg, Max Born, Wolfgang Pauli and their associates, becoming a science of probabilities based upon the Copenhagen interpretation of Niels Bohr. By 1930, the reformulated theory had been further unified and formalized by the work of Paul Dirac and John von Neumann, with a greater emphasis placed on measurement, the statistical nature of our knowledge of reality, and philosophical speculations about the role of the observer.
The Copenhagen interpretation quickly became (and remains) the orthodox interpretation. However, due to the absence of conclusive experimental evidence there are also many competing interpretations.
Quantum mechanics has since branched out into almost every aspect of physics, and into other disciplines such as 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.
“It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.”
MICHIO KAKU
MICHIO KAKU