theoretical physics

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Theoretical physics

The description of natural phenomena in mathematical form. It is impossible to separate theoretical physics from experimental physics, since a complete understanding of nature can be obtained only by the application of both theory and experiment. There are two main purposes of theoretical physics: the discovery of the fundamental laws of nature and the derivation of conclusions from these fundamental laws.

Physicists aim to reduce the number of laws to a minimum to have as far as possible a unified theory. When the laws are known, it is possible from any given initial conditions of a physical system to derive the subsequent events in the system. Sometimes, especially in quantum theory, only the probability of various events can be predicted. See Determinism, Quantum mechanics

The conclusions to be derived from the fundamental laws of nature may be of several different types.

1. Conclusions may be derived in order to test a given theory, particularly a new theory. An example is the derivation of the spectrum of the hydrogen atom from quantum mechanics; the verification of the predictions by accurate measurements is a good test of quantum mechanics. On rather rare occasions an experiment has been found to contradict the predictions of an existing theory, and this has then led to the discovery of important new physical laws. An example is the Michelson-Morley experiment on the constancy of the velocity of light, an experiment which led to special relativity theory. See Atomic structure and spectra, Light, Relativity

2. Theory may be required for experiments designed to determine physical constants. Most fundamental physical constants cannot be accurately measured directly. Elaborate theories may be required to deduce the constant from indirect experiments. See Fundamental constants

3. Predictions of physical phenomena may be made in order to gain understanding of the structure of the physical world. In this category fall theories of the structure of the atom leading to an understanding of the periodic system of elements, or of the structure of the nucleus in which various models are tested (for example, shell model or collective model). In the same category fall applications of theoretical physics to other sciences, for example, to chemistry (theory of the chemical bond and of the rate of chemical reactions), astronomy (theory of planetary motion, internal constitution, and energy production of stars), or biology.

4. Engineering applications may be drawn from fundamental laws. All of engineering may be considered an application of physics, and much of it is an application of mathematical physics, such as elasticity theory, aerodynamics, electricity, and magnetism. The generation and propagation of radio waves of all frequencies are examples of application of theoretical physics to direct practice. See Aerodynamics, Electricity, Magnetism

Apart from the classification of the fields of theoretical physics according to purpose, a classification can also be made according to content. Here one may perhaps distinguish three classification principles: type of force, scale of physical phenomena, and type of phenomena. See Mathematical physics, Physics

theoretical physics

[‚thē·ə′red·ə·kəl ′fiz·iks]
(physics)
The description of natural phenomena in mathematical form.
References in periodicals archive ?
The possibility of the existence of matter in such a new physical state was predicted in the 1920s by the outstanding theoretical physicists from India Shatendranat Bose (1894-1974) and Germany Albert Einstein (1879-1955) [1, 16].
One of the biggest extant challenges for theoretical physicists is reconciling relativity with quantum mechanics, and creating, in the process, what has long been known as a "theory of everything.
Whether their pet theories are right or wrong, many theoretical physicists are simply excited that the new LHC data can finally anchor existing ideas to reality.
TEHRAN (FNA)- Taking a well-known concept, theoretical physicists (of all people) observed for the first time that our DNA hides embedded instructions for the strands to fold a certain way - instructions that can also affect mutations.
When a reporter obliged, Mr Trudeau, a former teacher, gave a detailed and elaborate mini-lesson on the difference between normal and quantum computing, drawing laughter and applause from an audience of some of Canada's brightest theoretical physicists.
Riazuddin was one of Pakistan's top scientists and is widely known theoretical physicists in Pakistan and abroad.
THEORETICAL PHYSICISTS USED to dream of producing a "theory of everything" that would relate the two principal breakthroughs of 20th-century physics: quantum mechanics and Einstein's general theory of relativity.
Hawking heads a list of speakers including British Astronomer Royal Martin Rees, Nobel Prize-winning physicist Saul Perlmutter and Kip Thorne, one of the world's leading theoretical physicists.
This handbook is written in language intended to be comprehensible to both mathematicians and theoretical physicists, in particular advanced students and researchers working in differential geometry, string theory, and related areas.
Many theoretical physicists and mathematicians tried to extend the basic space-time of General Relativity during the last century, commencing in the 1910's.
00pm) This documentary examines the work of astronomers and theoretical physicists who are trying to map a black hole, in the hope of discovering whether they are the key to solving the mystery of what existed before the big bang.

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