Is - k Tr(ρlnρ) the Entropy in Quantum Mechanics
Bibliographic Data
| ID | 8396325 |
|---|---|
| Authors | O R Shenker (University of Oxford, corresponding author) |
| Year | 1999 |
| Volume | 50 |
| Issue | 1 |
| Pages | 33-48 |
| Publication date | 1999-03-01 |
| Open Access | No |
| Type | ARTICLE |
| Venue | The British Journal for the Philosophy of Science (JOURNAL) |
| Journal identifiers | ISSN: 0007-0882 • E-ISSN: 1464-3537 |
| Publisher | Oxford University Press (PUBLISHER • GB) |
| DOI | 10.1093/bjps/50.1.33 |
| OpenAlex | W2167310598 |
| Language | EN |
| Citations received | 7 |
| References cited | 15 |
In quantum mechanics, the expression for entropy is usually taken to be -kTr(ρlnρ), where ρ is the density matrix. The convention first appears in Von Neumann's Mathematical Foundations of Quantum Mechanics. The argument given there to justify this convention is the only one hitherto offered. All the arguments in the field refer to it at one point or another. Here this argument is shown to be invalid. Moreover, it is shown that, if entropy is -kTr(ρlnρ), then perpetual motion machines are possible. This and other considerations support the conclusion that this expression is not the quantum-mechanical correlate of thermodynamic entropy. Its usefulness in quantum-statistical mechanics can be explained by its being a convenient quantification of information, but information and entropy are not synonymous. As the present paper shows, one can change while the other is conserved.
Classical mechanics · Entropy (arrow of time) · Physics · Quantum · Quantum entanglement · Quantum mechanics · Statistical Mechanics · Statistical physics · Theoretical physics · Von Neumann entropy · Advanced Thermodynamics and Statistical Mechanics · Mathematical Physics · Mathematics · Quantum Mechanics and Applications · Statistical Mechanics and Entropy
| Citations per year | 0.28 |
|---|---|
| Citation span | 2001 - 2021 (21) |
| Highly cited | No |