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Related papers: Some positive thoughts about Negative Absolute Tem…

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Local temperature defined by a local canonical state of the respective subsystem, does not always exist in quantum many body systems. Here, we give some examples of how this breakdown of the temperature concept on small length scales might…

Statistical Mechanics · Physics 2009-11-10 Michael Hartmann , Guenther Mahler

The temperature of a physical system is operationally defined in physics as "that quantity which is measured by a thermometer" weakly coupled to, and at equilibrium with the system. This definition is unique only at global equilibrium in…

Statistical Mechanics · Physics 2020-01-08 Daochi Zhang , Xiao Zheng , Massimiliano Di Ventra

It has long been taken for granted that there is only one type of thermodynamic system near absolute zero temperature: the ordinary one compatible with all statements of the third law, with a fundamental yet tacit assumption that all heat…

Statistical Mechanics · Physics 2025-08-12 Q. H. Liu , S. F. Xiao , D. Guo , K. J. Yin

The physical quantity "temperature" is a cornerstone of thermodynamics and statistical physics. But it is necessary to mention that very frequently the scientists forget about the conditions to be satisfied in order to introduce…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 Dmitrii Tayurskii , Alain Le Méhauté

We review the general aspects of the concept of temperature in equilibrium and non-equilibrium statistical mechanics. Although temperature is an old and well-established notion, it still presents controversial facets. After a short…

Statistical Mechanics · Physics 2017-11-13 A. Puglisi , A. Sarracino , A. Vulpiani

In this paper we carefully reexamine the various framworks existing in the field of relativistic thermodynamics. We scrutinize in particular the different conceptual foundations of notions like the relativistic work, heat force, moving heat…

General Relativity and Quantum Cosmology · Physics 2008-01-21 Manfred Requardt

We discuss a simple toy model which allows, in a natural way, for deriving central facts from thermodynamics such as its fundamental laws, including Carnot's version of the second principle. Our viewpoint represents thermodynamic systems as…

Quantum Physics · Physics 2022-05-17 Ämin Baumeler , Carla Rieger , Stefan Wolf

A bath with a negative temperature is a subject of intense debate in recent times. It raises fundamental questions not only on our understanding of negative temperature of a bath in connection with thermodynamics but also on the…

Conversations about weather, environment, health, cuisine, and even politics, all involve the word "temperature". It was an attempt to understand the working of heat engines that gave the temperature a clear definition. In this Note we put…

Statistical Mechanics · Physics 2025-09-23 Miroslav Grmela

The concept of temperature is one of the key ideas in describing the thermodynamical properties of a physical system. In classical statistical mechanics of ideal gases, the notion of temperature can be described in two different ways, the…

Statistical Mechanics · Physics 2007-11-12 Krishna R. Narayanan , Arun R. Srinivasa

'Relativistic thermodynamics' should be understood not as a generalization of a non-relativistic theory but as an application of a general thermodynamic framework, neutral as to spacetime setting and allowing arbitrary conserved quantities,…

Statistical Mechanics · Physics 2025-08-06 David Wallace

One of the most intriguing features of string thermodynamics is thermal duality, which relates the physics at temperature T to the physics at inverse temperature 1/T. Unfortunately, the traditional definitions of thermodynamic quantities…

High Energy Physics - Theory · Physics 2007-05-23 Keith R. Dienes , Michael Lennek

It is shown that the proof of [1] that the specific heat of the system of classical point particles interacting with each other via uniform gravitational potential energy may be negative is incorrect.

General Physics · Physics 2017-05-03 Ikhtier H. Umirzakov

The solutions of a particle's Dirac equation contains a negative kinetic energy (NKE) branch. Such an energy spectrum has an upper limit but no lower limit, so that the system with this spectrum, called NKE system, is of negative…

General Physics · Physics 2021-06-18 Huai-Yu Wang

The second law of thermodynamics constitutes a fundamental principle of physics, precluding the existence of perpetual motion machines and providing a natural definition of the arrow of time. Its scope extends across virtually all areas of…

General Relativity and Quantum Cosmology · Physics 2025-10-21 Alejandro Corichi , Omar Gallegos

Measuring the local temperature of nanoscale systems out of equilibrium has emerged as a new tool to study local heating effects and other local thermal properties of systems driven by external fields. Although various experimental…

Mesoscale and Nanoscale Physics · Physics 2016-12-07 LvZhou Ye , Xiao Zheng , YiJing Yan , Massimiliano Di Ventra

A general expression for the temperature of a finite-dimensional quantum system is deduced from thermodynamic arguments. At equilibrium, this magnitude coincides with the standard thermodynamic temperature. Furthermore, it is well-defined…

Quantum Physics · Physics 2020-05-04 Andrés Vallejo , Alejandro Romanelli , Raúl Donángelo

This review presents the effective temperature notion as defined from the deviations from the equilibrium fluctuation-dissipation theorem in out of equilibrium systems with slow dynamics. The thermodynamic meaning of this quantity is…

Statistical Mechanics · Physics 2015-05-28 Leticia F. Cugliandolo

The meaning of temperature in nonequilibrium thermodynamics is considered by using a forced harmonic oscillator in a heat bath, where we have two effective temperatures for the position and the momentum, respectively. We invent a concrete…

Statistical Mechanics · Physics 2007-05-23 Takahiro Hatano , David Jou

Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al (2013) has…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-23 J. P. P. Vieira , Christian T. Byrnes , Antony Lewis