Where is the theory of quantum mechanics? What is the theory of quantum mechanics

Quantum mechanics is a branch of physics that studies the motion of microscopic particles in the material world, mainly studying the basic theory of the structure and properties of atoms, molecules, condensed matter, atomic nuclei and elementary particles. Together with the theory of relativity, it forms the theoretical basis of modern physics. Quantum mechanics is not only one of the basic theories of modern physics, but also widely used in disciplines such as chemistry and many modern technologies.

At the end of the 19th century, it was discovered that the old classical theories could not explain microscopic systems, so through the efforts of physicists, quantum mechanics was created in the early 20th century to explain these phenomena. Quantum mechanics has fundamentally changed our understanding of the structure of matter and its interactions. With the exception of gravity, which is described by the general theory of relativity, all fundamental interactions to date can be described within the framework of quantum mechanics (quantum field theory).

Quantum mechanics is the theory of describing microscopic matter, which, along with the theory of relativity, is considered to be the two fundamental pillars of modern physics, and many physical theories and sciences such as atomic physics, solid state physics, nuclear physics, and particle physics, as well as other related disciplines, are based on quantum mechanics.

Quantum mechanics is a very small field -- the main physics theory of subatomic particles. This theory was formed in the early 20th century and revolutionized people's understanding of the composition of matter. In the microcosm, particles are not billiard balls, but buzzing probabilistic clouds that do not exist in more than one location and do not reach point B from point A through a single path.

According to quantum theory, particles often behave like waves, and the "wave function" used to describe particle behavior is a possible property of a particle, such as its position and velocity, rather than deterministic properties. Some of the weird concepts in physics, such as the principle of entanglement and uncertainty, have their roots in quantum mechanics. <>

Concept 1: Hilbert Space.

A complete complex product space is called a Hilbert space. The inner product is a positively definite, conjugate-symmetric, semi-conjugate linear semilinear binary function in linear space, which brings orthogonality, length, and topology to linear space. For an infinite dimensional space, the topology determines the structure of the space, and it can be seen whether a space is complete, and there are holes in incomplete spaces, and only by filling the holes can it be possible to make:

1.There is a set of orthogonal normalized bases such that any state vector can be on the basis.

2.Each state vector corresponds to a bounded linear functional. This is completeness, and without this guarantee, we can't make any state represent as a superposition of some basic states, and we can't think that the left and right vectors are one-to-one.

Concept 2: Divisible.

A topological space with a countable dense subset is called divisible. Countable means finite or can be mapped one-to-one with natural numbers, although the set is infinite, but we can arrange the elements one by one, from the first, the second, the third, infinitely. Integers are countable, rational numbers are countable, algebraic numbers are countable, and real numbers are not countable.

Dense means that the closure of this collection is full space. For distance space, dense is equivalent to, for any point a and for any small distance d, I can find a point in this set so that it is less than d distance from a. Rational numbers are densely packed in real numbers, so real numbers are divisible.

A divisible Hilbert space always has a handful of orthogonal unified, and there is always a vector that is not orthogonal to all the bases. In an indivisible Hilbert space, there are uncountable orthogonal unification bases, but any vector is not orthogonal to a countable basis at most. That is, only in divisible space, I dare to assert that there is a state vector whose components on all bases are nothing!

In quantum mechanics, the state of a physical system is represented by a state function, and an arbitrary linear superposition of the state function still represents one of the possible states of the system. The change of state over time follows a linear differential equation that predicts the behavior of the system, and the physical quantities are represented by operators representing certain operations that meet certain conditions; The operation of measuring a physical quantity of a physical system in a certain state corresponds to the effect of the operator representing that quantity on its state function; The possible value of the measurement is determined by the eigenequation of the operator, and the expected value of the measurement is calculated by an integral equation containing the operator. (In general, quantum mechanics does not definitively predict a single outcome for an observation.)

Instead, it predicts a set of different outcomes that may occur and tells us the probability of each outcome occurring. That is, if we measure a large number of similar systems in the same way, each of which starts in the same way, we will find that the result of the measurement is a certain number of times, for b a different number of times, and so on. One can predict an approximation of the number of occurrences of a or b outcome, but cannot make predictions about a specific outcome for individual measurements.

The modulus square of the state function represents the probability of occurrence of a physical quantity as its variable. Based on these basic principles and accompanied by other necessary assumptions, quantum mechanics can explain various phenomena of atoms and subatoms. <>

The unified field theory comprehensively explains the phenomena and processes of the existence and change of matter in the universe, and realizes the unity of the theory of nature.

Quantum Mechanics (English: Quantum Mechanics; Quantum theory is a physical theory that describes the behavior of microscopic matter (atoms, subatomic particles), and quantum mechanics is the basis for our understanding of all fundamental forces (electromagnetic, strong, weak) except for gravitation.

Quantum mechanics is the foundation of many branches of physics, including electromagnetism, particle physics, condensed matter physics, and parts of cosmology. Quantum mechanics is also the foundation of disciplines such as chemical bond theory, structural biology, and electronics.

Quantum mechanics is mainly used to describe the behavior of microscopic conditions, and the particles described cannot be accurately interpreted by classical mechanics. For example, according to the Copenhagen interpretation, a particle does not have any physical properties before it is observed, but after it is observed, depending on the measuring instrument, its particle properties may be observed, its wave properties may be observed, or some particle properties and part of the wave properties may be observed, which is wave-particle duality.

Quantum mechanics began in the early 20th century with the seminal work of Max Planck and Niels Bohr, who coined the term "quantum mechanics" in 1924. Because of its success in explaining experimental phenomena that could not be explained by classical mechanics, and accurately predicting some subsequent discoveries, this new theory began to be widely accepted by the physics community. One of the major early achievements of quantum mechanics was the successful explanation of wave-particle duality, a term derived from the fact that subatomic particles exhibit the properties of both particles and waves.

In the form of quantum mechanical Kaicode, the state of the system at a given time is described by the complex wave function, also known as the state vector in the complex vector space. [24] This abstract mathematical object allows the calculation of the probability of concrete experimental results. For example, it allows calculating the probability of finding an electron in a specific region around the nucleus at a specific time.

Contrary to classical mechanics, one can never conjugate physical quantities such as position and momentum at the same time with arbitrary precision. For example, electrons can be thought to be (with a certain probability) located somewhere within a given region of space, but their exact location is unknown.

The outline of a constant probability density, often referred to as a "cloud," can be drawn around the nucleus of an atom to conceptualize the most likely location of an electron. Heisenberg's uncertainty principle quantifies the ability of a particle to be pinpointed due to its conjugate momentum. [25]

Quantum mechanics is the basic theory for understanding physical phenomena at the subatomic scale. It was developed in the early 20th century and was based on the results of some special experiments and new ways of thinking. Just as classical physics describes the laws of macroscopic objects, quantum mechanics describes the laws of microscopic particles (e.g., electrons, protons, neutrons, etc.), which plays a very important role in our understanding of the microscopic world of nature.

Quantum mechanics has many wonderful concepts and laws. The most well-known of these is wave-particle duality and the uncertainty principle. According to wave-particle duality, these microscopic particles can either evolve like waves, or they can have properties such as position and momentum like particles.

At the microscopic level, the state of motion of particles cannot be completely **, and this chaotic state is uncertainty. The uncertainty is related to the fact that the results of the observation operation inevitably interfere with the original state of the system.

In addition, transient phenomena, discrete phenomena, matrix mechanics, and relativistic quantum mechanics are the core theories of quantum mechanics, which provide effective methods for us to deal with various complex situations.

Quantum mechanics has a wide range of applications in a variety of fields, including atomic physics, chemistry, semiconductor electronics, quantum computers, and quantum communications. Among them, the application of semiconductor physics is the most significant. In the field of nanoelectronics, as the size of modern electronic devices has been reduced to the same order of magnitude as microscopic particles, accurate calculations have become a necessary technology instead of traditional wind measurement.

With the rapid development of quantum mechanics, more and more researchers are committed to exploring its deeper nature and applications. The establishment of a new quantum communication network and the construction of a practical "hardware quantum computer" in the true sense of the word have all promoted the prosperity and progress of the field of quantum mechanics. At the same time, there are also areas such as the problem of information loss in black holes, "faster-than-light" transmission events, etc., these unsolved scientific questions lead us to think about the possible new laws of physics.

To sum up, quantum mechanics is a basic branch of physics that studies the state of motion of microscopic particles and their essential laws. Among the various novel and bizarre phenomena, quantum mechanics has given mankind a new understanding of the microscopic world and helped us explore the mysteries of the natural world. The efforts of modern scholars in theoretical exploration and practical applications will continue to advance the development of science and technology, creating new fields that will make important contributions to human life.

Quantum mechanics is the branch of physics that studies the microscopic world, and it deals with the behavior of atoms, molecules, and elementary particles. Here are a few popular examples to explain quantum mechanics:

1.Double-slit experiment: This experiment can demonstrate one of the fundamental properties of quantum physics:

Wave-particle duality. In the double-slit experiment, photons are emitted through two slits and hit on the back of the sail. Experiments have shown that photons exhibit the behavior of both particles and waves.

2.Cat Thought Experiment: This experiment can explain the concept of quantum superposition states.

In a cat thought experiment, a cat was packed in an airtight box with a sample of radioactive material. When the sedan car decays, the radiation released kills the cat. According to the superposition principle of quantum mechanics, the cat is in a superposition state, i.e., the cat may be both alive and dead before the box is opened.

3.Quantum tunneling effect: This phenomenon can be explained by the fact that some particles pass through a seemingly impossible obstacle without sufficient energy. This phenomenon is widely used in the design and production of electronic devices.

The above are a few popular examples to explain the concepts of quantum mechanics, although the concepts of quantum mechanics are more abstract, these examples can help people better understand the basic concepts and principles in quantum physics.