Entropy production is a key quantity in any finite-time thermodynamic process. It intimately tied with the fundamental laws of thermodynamics, embodying tool to extend considerations all way non-equilibrium processes. also often used attempts provide quantitative characterization logical and irreversibility, stemming from processes physics, chemistry biology. Notwithstanding its character, unifying theory entropy valid for general processes, both classical quantum, has not yet been...

The study of open quantum systems often relies on approximate master equations derived under the assumptions weak coupling to environment. However when system is made several interacting subsystems such a derivation in many cases very hard. An alternative method, employed especially modelling transport mesoscopic systems, consists using {\it local} containing Lindblad operators acting locally only corresponding subsystem. It has been shown that this approach however generates inconsistencies...

Thermodynamic uncertainty relations (TURs) place strict bounds on the fluctuations of thermodynamic quantities in terms associated entropy production. In this Letter, we identify tightest (and saturable) matrix-valued TUR that can be derived from exchange fluctuation theorems describing statistics heat and particle flow between multiple systems arbitrary dimensions. Our result holds for both quantum classical systems, undergoing general finite-time nonstationary processes. Moreover, it...

Thermodynamic irreversibility is well characterized by the entropy production arising from non-equilibrium quantum processes. We show that of a system undergoing open-system dynamics can be formally split into term only depends on population unbalances, and one underpinned coherences. The unbalances are found to contribute both an flux rate. decoherence, other hand, contributes This allows us identify genuine contribution in make use such division address spin $J$ particle, which we describe...

Heat spontaneously flows from hot to cold in standard thermodynamics. However, the latter theory presupposes absence of initial correlations between interacting systems. We here experimentally demonstrate reversal heat flow for two quantum correlated spins-1/2, initially prepared local thermal states at different effective temperatures, employing a Nuclear Magnetic Resonance setup. observe spontaneous energy system. This process is enabled by trade off and entropy that we quantify with...

Systems whose boundaries are in contact with heat baths at different temperatures allow for the realization of nonequilibrium steady states (NESS) characterized by distribution functions that still time independent, yet from equilibrium distributions. Such have interesting properties even classical statistical mechanics, but recently their quantum analogs received attention, both fundamental and applied reasons. This review provides an account recent progress this field. It introduces...

A pedagogical overview of analytical and numerical techniques used to characterize current fluctuations in Markovian systems is presented, helping bridge knowledge between condensed-matter physics quantum optics.

The kinetic uncertainty relation (KUR) bounds the signal-to-noise ratio of stochastic currents in terms number transitions per unit time, known as dynamical activity. This bound was derived a classical context and can be violated quantum regime due to coherent effects. However, precise connection between KUR violations coherence has so far remained elusive, despite significant investigation. In this Letter, we solve problem by deriving modified that exactly pinpoints how, when, might lead...

Considerable effort has been made in recent years to optimize materials properties for magnetic hyperthermia applications. However, due the complexity of problem, several aspects pertaining combined influence different parameters involved still remain unclear. In this paper, we discuss detail role anisotropy on specific absorption rate cobalt-ferrite nanoparticles with diameters ranging from 3 14 nm. The structural characterization was carried out using x-ray diffraction and Rietveld...

The dynamic properties of magnetic nanoparticles are known to be substantially influenced by the dipole-dipole interaction. In this paper we study how affects efficiency hyperthermia experiments. particular ask whether it is possible use dipolar interaction as a mechanism increase heat released nanoparticles, thus improving application. investigation carried out via numerical simulations based on mean-field model developed include in Fokker-Planck equation describing time evolution system....

Further advances in magnetic hyperthermia might be limited by biological constraints, such as using sufficiently low frequencies and field amplitudes to inhibit harmful eddy currents inside the patient's body. These incite need optimize heating efficiency of nanoparticles, referred specific absorption rate (SAR). Among several properties currently under research, one particular importance is transition from linear non-linear regime that takes place amplitude increased, an aspect where...

Thermal rectification is the phenomenon by which flux of heat depends on direction flow. It has attracted much interest in recent years due to possibility devising thermal diodes. In this paper, we consider quantum XXZ chain subject an inhomogeneous field. The driven out equilibrium contact at its boundaries with two different reservoirs, leading a constant flow magnetization from one bath other. nonunitary dynamics system, modeled Lindblad master equation, treated exactly for small sizes...

We introduce the idea of weakly coherent collisional models, where elements an environment interacting with a system interest are prepared in states that approximately thermal but have amount coherence proportional to short system-environment interaction time scenario akin well-known models. show that, continuous-time limit, model allows for clear formulation first and second laws thermodynamics, which modified include nontrivial contribution related quantum coherence. Remarkably, we derive...

We introduce a general framework for thermometry based on collisional models, where ancillas probe the temperature of environment through an intermediary system. This allows generation correlated even if they are initially independent. Using tools from parameter estimation theory, we show minimal qubit model that individual can already outperform thermal Cramer-Rao bound. In addition, due to steady-state nature our model, when measured collectively always exhibit superlinear scalings Fisher...

A proposed theoretical framework for irreversible entropy production is applied to quantum systems in contact with non-equilibrium reservoirs; previous frameworks have been restricted equilibrium reservoirs.

We derive detailed and integral quantum fluctuation theorems for heat exchange in a correlated bipartite thermal system using the framework of dynamic Bayesian networks. Contrary to usual two-projective-measurement scheme that is known destroy features, these relations fully capture correlations coherence at arbitrary times. further obtain individual classical correlations, as well local global coherences.

A deeper understanding of the differences between quantum and classical dynamics promises great potential for emerging technologies. Nevertheless, some aspects remain poorly understood, particularly concerning role coherence in open systems. On one hand, leads to entanglement even nonlocality. other, it may lead a suppression fluctuations, causing violations thermokinetic uncertainty relations (TUR KUR) that are valid processes. These represent two different manifestations coherence,...

By making use of a recently proposed framework for the inference thermodynamic irreversibility in bosonic quantum systems, we experimentally measure and characterize entropy production rates nonequilibrium steady state two different physical systems—a micromechanical resonator Bose-Einstein condensate—each coupled to high finesse cavity hence also subject optical loss. Key features our setups, such as cooling mechanical signatures structural phase transition condensate, are reflected rates....

Autonomous engines operating at the nano-scale can be prone to deleterious fluctuations in heat and particle currents which increase, for fixed power output, more reversible operation regime is. This fundamental trade-off between current entropy production forms basis of recently formulated thermodynamic uncertainty relations (TURs). However, these have so far only been derived classical Markovian systems violated quantum regime. In this paper we show that geometry non-equilibrium...

Modern quantum experiments provide examples of transport with noncommuting quantities, offering a tool to understand the interplay between thermal and effects. Here we set forth theory for non-Abelian in linear response regime. Our key insight is use generalized Gibbs ensembles charges as basic building blocks strict charge-preserving unitaries collisional setup. The framework then built using model two reservoirs. We show that coefficients obey Onsager reciprocity. Moreover, find coherence,...

Quantum thermometry exploits the high level of control in coherent devices to offer enhanced precision for temperature estimation. This highlights need constructing concrete estimation strategies. Of particular importance is collisional thermometry, where a series ancillae are sent sequentially probe system's temperature. In this paper we put forth complete framework analyzing using Bayesian inference. The approach easily implementable and experimentally friendly. Moreover, it guaranteed...

In the mesoscopic leads technique, continuum environments at finite temperature are modeled via a finite-set modes, which in turn damped by Markovian dissipation. Here, authors extended this approach to include arbitrary time dependence Hamiltonian of central system and performed detailed assessment thermodynamic quantities. They illustrated their applying technique driven resonant level model double dot system, is noninteracting exhibiting rectification.

Abstract Many real-world tasks include some kind of parameter estimation, i.e. the determination a encoded in probability distribution. Often, such distributions arise from stochastic processes. For stationary process with temporal correlations, random variables that constitute it are identically distributed but not independent. This is case, for instance, quantum continuous measurements. In this article, we derive asymptotic Fisher information rate finite Markov order. We give precise...

Landauer's bound relates changes in the entropy of a system with inevitable dissipation heat to environment. The bound, however, becomes trivial limit zero temperature. Here we show that it is possible derive tighter which remains nontrivial even as $T\ensuremath{\rightarrow}0$. As original case, only assumption make environment thermal state. Nothing said about state or kind system-environment interaction. Our valid for all temperatures and always than one, tending high temperatures.

Fluctuation theorems are fundamental extensions of the second law thermodynamics for small systems. Their general validity arbitrarily far from equilibrium makes them invaluable in nonequilibrium physics. So far, experimental studies quantum fluctuation relations do not account correlations and coherence, two essential properties. We here apply a novel dynamic Bayesian network approach to experimentally test detailed integral fully heat exchange between quantum-correlated thermal spins-1/2...