Local temperatures of strongly-correlated quantum dots out of equilibrium

Abstract

Probes that measure the local thermal properties of systems out of equilibrium are emerging as new tools in the study of nanoscale systems. One can then measure the temperature of a probe that is weakly coupled to a bias-driven system. By tuning the probe temperature so that the expectation value of some observable of the system is minimally perturbed, one obtains a parameter that measures its degree of local statistical excitation, and hence its local heating. However, one anticipates that different observables may lead to different temperatures and thus different local heating expectations. We propose an experimentally realizable protocol to measure such local temperatures and apply it to bias-driven quantum dots. By means of a highly accurate open quantum system approach, we show theoretically that the measured temperature is quite insensitive both to the choice of observable and to the probe-system coupling. In particular, even with observables that are distinct both physically and in their degree of locality, such as the local magnetic susceptibility of the quantum dot and the global spin-polarized current measured at the leads, the resulting local temperatures are quantitatively similar for quantum dots ranging from noninteracting to Kondo-correlated regimes, and are close to those obtained with the traditional "local equilibrium" definition.

Revealing the Phenomena of Heat and Photon Energy on Dealing Matter at Atomic level

“…To measure temperature of such materials and in their selective sizes is the integral part to understand science of their different behaviours and some of the studies shed light on it [40][41][42]. It is possible to measure temperature of atoms, their nanoscale components and at bulk scale as well without the involvement of thermocouples and introducing various gadgets, theories, etc.…”

Thermodynamic meaning of local temperature of nonequilibrium open quantum systems

“…Such local heating affects crucially the device properties [13][14][15][16], and have significant influence on some physical processes, such as thermoelectric conversion [17][18][19], heat dissipation [8,19], and electron-phonon interactions [20,21]. All these studies, however, leave open the question of what precisely is a "local temperature" in a nonequilibrium system, a concept that has a well-established meaning only in global equilibrium.Over the past decade, numerous experimental [15,[22][23][24][25][26][27] and theoretical [28][29][30][31][32][33][34][35][36][37][38] efforts have been made to provide practical and meaningful definitions of local temperature for nonequilibrium systems that bear a close conceptual resemblance to the thermodynamic one. However, it has remained largely unclear how to physically interpret the defined local temperature, and how to associate the measured value with the magnitudes of local excitations and local heating at a quantitative level.…”

Revealing the Phenomena of Heat and Photon Energy on Dealing Matter at Atomic level

“…Our recent study shows the developing particles of predictor packing where force and energy engaged together in certain manner [41]. To measure temperature of such materials is the integral part to understand science of their different behaviours and some of the studies shed light on it [42][43][44]. It is possible to measure temperature of atoms, their nanoscale components and at bulk scale as well without the involvement of thermocouples and the introduction of various gadgets, theories, etc.…”