What is entropy? What are the applications in the social sciences?

Entropy refers to the degree of chaos in the system, and it has important applications in cybernetics, probability theory, number theory, astrophysics, life sciences and other fields. Entropy was proposed by Rudolf Clausius and applied in thermodynamics. Later, Claude Elwood Shannon first introduced the concept of entropy to information theory.

The popular understanding of entropy is as follows:The popular explanation is: entropy is an indicator of the degree of chaos of things in our world, the degree to which things are close to a chaotic state, and the more disordered things are, the more chaotic they are, and the greater the entropy.

Conversely, the entropy is small. There is always a tendency for any isolated system to change from high order to low order. This is the principle of entropy increase.

It is difficult to make a paper that is particularly flat when the smell always dissipates and wrinkles over time.

The concept of entropy is proposed:Around 1877, Boltzmann proposed a statistical-physical explanation of entropy. He proved in a series of **:

The macroscopic physical properties of the system can be thought of as the isoprobabilistic statistical average of all possible microscopic states.

For example, consider the ideal gas inside a container. The microstate can be expressed in terms of the position and momentum of each gas atom. All possible microstates must meet the following conditions:

All particles are located within the volume of the container; The sum of the kinetic energy of all the atoms is equal to the total energy value of that gas.

Entropy is a measure of the state of certain material systems, and the degree to which certain states of material systems are likely to occur. It is also used by the social sciences to refer to the extent of certain states of human society. The concept of entropy was proposed by the German physicist Clausius in 1865.

Entropy was originally used to describe the "degradation of energy" as one of the parameters of the state of matter and has a wide range of applications in thermodynamics. However, at that time, entropy was only a physical quantity that could be measured by the change of heat, and its essence was still not well explained, until a series of scientific theories such as statistical physics and information theory developed, and the essence of entropy was gradually explained, that is, the essence of entropy is the "internal chaos degree" of a system. It has important applications in cybernetics, probability theory, number theory, astrophysics, life sciences and other fields, and there are more specific definitions in different disciplines.

Entropy, one of the parameters in thermodynamics that characterize the state of matter, is denoted by the symbol s, and its physical meaning is a measure of the degree of chaos in the system.

Principle: The entropy of an isolated system never decreases automatically, and the entropy does not change in a reversible process and increases in an irreversible process. The principle of entropy increase is another formulation of the second law of thermodynamics, which points out the direction of irreversible processes in a more general way than Kelvin and Clausius. At the same time, it is more profoundly pointed out that the second law of thermodynamics is a statistical law of the irregular motion of a large number of molecules, so it is only applicable to systems composed of a large number of molecules, and is not applicable to systems composed of a single molecule or a small number of molecules.

Relation: Entropy and Society, Economics, and Management Conventional view: the concept of energy is more important than the concept of entropy; Because energy dominates everything in the universe (energy must be conserved), entropy is a vassal of energy, and it is a further indication of the direction in which the process proceeds under the premise of conservation of energy.

Energy is regarded as the mistress of the universe, and entropy is her shadow Modern view: Entropy is associated with ineffective energy, chaos, waste, pollution, ecological environment destruction, waste of material resources, and even political and social corruption, and negative entropy is associated with order, structure, information, life, and even clean government, and spiritual civilization Boltzmann's statistical mechanics has achieved great success in studying the thermal properties and reversible processes of equilibrium systems, and the macroscopic thermodynamic laws are well explained by microscopic molecular motion.

After Boltzmann's death, many physicists made further studies of non-equilibrium and irreversible processes. In 1947, Prigogine proposed the principle of minimum entropy generation, pointing out that in equilibrium, there is no entropy generation (i.e., the entropy generation rate is zero); In the irreversible process of "near-equilibrium", although entropy is generated, the rate of entropy generation tends to be the smallest. Prigogine was deeply influenced by the famous philosopher Bergson's idea of time as "creation" and "evolution".

In the evolution of biology and society, we see the evolution from disorder to order, from simple to complex.

Entropy s is a function of the state, which has the property of addition (capacity) and is a non-conserved quantity of breadth measurement, since the heat in its definition is proportional to the amount of matter, but the definite state has a definite quantity. The amount of change δs is only determined by the consistent state of the system and has nothing to do with whether the process is reversible or not. Since the change in the entropy of the system is equal to the sum of the heat-temperature quotient δq t of the reversible process, the entropy change of the system can only be obtained by the reversible process.

The reversible change process of isolated system or adiabatic reversible change δs=0.

Macroscopic entropy is a macroscopic quantity, which is a property of the large number of microscopic ions that make up the system collectively. It includes the entropy contributed by the translation, vibration, rotation, electron motion, and nuclear spin motion of molecules, and it is meaningless to talk about the entropy of individual microscopic particles.

The absolute value of absolute entropy cannot be determined by the second law of thermodynamics. The absolute value of entropy can be determined by the third law according to the calorimetry data, which is called prescribed entropy or calorimetry. The absolute value of entropy can also be calculated from the microstructure data of the molecule by statistical thermodynamic methods, which is called statistical entropy or spectral entropy.

Entropy is now not only a thermodynamic concept, but its field of study has been designed to explain phenomena in the fields of philosophy, life science, informatics, etc.

Entropy: Entropy is one of the important state functions that describe thermodynamic systems. The magnitude of entropy reflects the stability of the state of the system, and the change of entropy indicates the direction in which the thermodynamic process proceeds, and entropy provides a quantitative expression for the second law of thermodynamics.

Thermodynamic definition of entropy:

1. Clausius proposed the concept of entropy for the first time from a macroscopic perspective, and its calculation formula is: s=q t, (when calculating the entropy difference, the formula should be q).

2. Boltzmann also proposed the concept of entropy from a microscopic perspective, the formula is: s=kln, which is the number of microscopic states, and usually uses s as a quantity to describe the degree of chaos.

3. In view of the current situation that it is not easy to understand and inconvenient to use, it is considered that it is proportional to the macroscopic parameters of the ideal gas system, that is: (t)=(t t)3 2 , v)=v v, the volume entropy of the ideal gas is sv=kln v=klnv, the temperature entropy is st=kln t=(3 2)klnt, and the entropy difference formula for calculating any process is s=(3 2)kln(t).'/t)+kln(v'v), this microscopic and macroscopic relationship and entropy formula have the characteristics of easy to understand and use, which is conducive to teaching and learning, and can be called the third generation of entropy formula.

The above three generations of entropy formulas use physical quantities that have in form"Intuitive Abstract Intuitive"We believe that this is not a conceptual game, but a leap forward in the understanding of the concept of entropy.

Entropy contains many meanings, I don't know which aspect you want to know? Originally, entropy represented the intensity of energy distribution in the physical realm, and then it was used in many fields, such as pollution, population ratio, information, and finance.

Entropy can be simply understood as the "degree of chaos".

Principle of entropy increase.

That is, the entropy only increases, not decreases.

It has a terrible prophecy of a man.

It is the existence of the "end of the world".

In information theory, entropy is used to measure the expected value of the occurrence of a random variable. It represents the amount of information lost during signal transmission before it is received, also known as information entropy. Information entropy is also known as source entropy and average self-information.

In 1948, Claude Ellwood Shannon introduced thermodynamic entropy into information theory, so it is also called Shannon entropy.

Information is a very abstract concept. We often say that there is a lot of information, or there is little information, but it is difficult to say exactly how much information there is. How much information is more than a 500,000-word Chinese book.

Entropy represents a physical quantity (denoted s) of the state of a material system, which indicates the degree to which that state is likely to occur. In thermodynamics, it is a relatively abstract physical quantity used to explain the irreversibility of thermal processes. The processes that actually take place in an isolated system necessarily increase its entropy.

Entropy is a physical term, generally speaking, it is an indicator to measure the degree of chaos in our world, and the second law of thermodynamics believes that isolated systems always have a tendency to change from high order to low order, which is the explanation of entropy.

The second law of thermodynamics (secondlaw of thermodynamics), one of the fundamental laws of thermocontinental petrology, Clausius stated that heat cannot be spontaneously transferred from a cold object to a high temperature object. Kelvin is stated as:

It is not possible to draw heat from a single heat source so that Liang Mingzhi can completely convert it into useful work without other effects.