|
The de Broglie–Bohm theory, also known as the pilot-wave theory, Bohmian mechanics, the Bohm or Bohm's interpretation, and the causal interpretation, is an interpretation of quantum theory. In addition to a wavefunction on the space of all possible configurations, it also postulates an actual configuration that exists even when unobserved. The evolution over time of the configuration (that is, of the positions of all particles or the configuration of all fields) is defined by the wave function via a guiding equation. The evolution of the wave function over time is given by Schrödinger's equation. The theory is named after Louis de Broglie (1892–1987), and David Bohm (1917–1992). The theory is deterministic〔 ("In contrast to the usual interpretation, this alternative interpretation permits us to conceive of each individual system as being in a precisely definable state, whose changes with time are determined by definite laws, analogous to (but not identical with) the classical equations of motion. Quantum-mechanical probabilities are regarded (like their counterparts in classical statistical mechanics) as only a practical necessity and not as an inherent lack of complete determination in the properties of matter at the quantum level.")〕 and explicitly nonlocal: the velocity of any one particle depends on the value of the guiding equation, which depends on the configuration of the system given by its wavefunction; the latter depends on the boundary conditions of the system, which in principle may be the entire universe. The theory results in a measurement formalism, analogous to thermodynamics for classical mechanics, that yields the standard quantum formalism generally associated with the Copenhagen interpretation. The theory's explicit non-locality resolves the "measurement problem", which is conventionally delegated to the topic of interpretations of quantum mechanics in the Copenhagen interpretation. The Born rule in Broglie–Bohm theory is not a basic law. Rather, in this theory the link between the probability density and the wave function has the status of a hypothesis, called the quantum equilibrium hypothesis, which is additional to the basic principles governing the wave function. The theory was historically developed by de Broglie in the 1920s, who in 1927 was persuaded to abandon it in favour of the then-mainstream Copenhagen interpretation. David Bohm, dissatisfied with the prevailing orthodoxy, rediscovered de Broglie's pilot wave theory in 1952. Bohm's suggestions were not widely received then, partly due to reasons unrelated to their content, connected to Bohm's youthful communist affiliations.〔F. David Peat, ''Infinite Potential: The Life and Times of David Bohm'' (1997), p. 133. James T. Cushing, ''Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony'' (1994) discusses "the hegemony of the Copenhagen interpretation of quantum mechanics" over theories like Bohmian mechanics as an example of how the acceptance of scientific theories may be guided by social aspects. 〕 De Broglie–Bohm theory was widely deemed unacceptable by mainstream theorists, mostly because of its explicit non-locality. Bell's theorem (1964) was inspired by Bell's discovery of the work of David Bohm and his subsequent wondering if the obvious nonlocality of the theory could be eliminated. Since the 1990s, there has been renewed interest in formulating extensions to de Broglie–Bohm theory, attempting to reconcile it with special relativity and quantum field theory, besides other features such as spin or curved spatial geometries. 〔David Bohm and Basil J. Hiley, ''The Undivided Universe - An Ontological Interpretation of Quantum Theory'' appreared after Bohm's death, in 1993; (reviewed ) by Sheldon Goldstein in ''Physics Today'' (1994). J. Cushing, A. Fine, S. Goldstein (eds.), ''Bohmian Mechanics and Quantum Theory - An Appraisal'' (1996).〕 The ''Stanford Encyclopedia of Philosophy'' article on Quantum decoherence ((Guido Bacciagaluppi, 2012 )) groups "approaches to quantum mechanics" into five groups, of which "pilot-wave theories" are one (the others being the Copenhagen interpretation, objective collapse theories, many-world interpretations and modal interpretations). There are several equivalent mathematical formulations of the theory and it is known by a number of different names. The de Broglie wave has a macroscopic analogy termed Faraday wave.〔John W. M. Bush: ("Quantum mechanics writ large" )〕 ==Overview== De Broglie–Bohm theory is based on the following postulates: * There is a configuration of the universe, described by coordinates , which is an element of the configuration space . The configuration space is different for different versions of pilot wave theory. For example, this may be the space of positions of particles, or, in case of field theory, the space of field configurations . The configuration evolves (for spin=0) according to the guiding equation :. Where is the probability current or probability flux and This already completes the specification of the theory for any quantum theory with Hamilton operator of type . * The configuration is distributed according to at some moment of time , and this consequently holds for all times. Such a state is named quantum equilibrium. With quantum equilibrium, this theory agrees with the results of standard quantum mechanics. Notably, even if this latter relation is frequently presented as an axiom of the theory, in Bohm's original papers of 1952 it was presented as derivable from statistical-mechanical arguments. This argument was further supported by the work of Bohm in 1953 and was substantiated by Vigier and Bohm's paper of 1954 in which they introduced stochastic ''fluid fluctuations'' that drive a process of asymptotic relaxation from quantum non-equilibrium to quantum equilibrium (ρ → |ψ|2).〔Publications of D. Bohm in 1952 and 1953 and of J.-P. Vigier in 1954 as cited in (p. 254 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「De Broglie–Bohm theory」の詳細全文を読む スポンサード リンク
|