Abstract The trade-off between robustness and tunability is a central challenge in the pursuit of quantum simulation fault-tolerant computation. In particular, architectures are often designed to achieve high coherence at expense tunability. Many current qubit designs have fixed energy levels consequently limited types controllable interactions. Here by adiabatically transforming fixed-frequency superconducting circuits into modifiable Floquet qubits, we demonstrate an XXZ Heisenberg...

We analyze a simple implementation of an absorption refrigerator, system that requires heat and not work to achieve refrigeration, based on two Coulomb coupled single-electron systems. analytically determine the general condition cooling-by-heating, we parameters simultaneously maximize cooling power coefficient performance (COP) finding displays particularly COP can reach Carnot's upper limit. also find be indirectly determined by measuring charge current. Analyzing as autonomous Maxwell...

A quantum thermal machine can be controlled by time-periodic perturbations that define a cycle, as in conventional macroscopic machines. This paper presents general and unified approach to the study of machines, including both heat engines refrigerators, which operate under periodic adiabatic driving are contact with reservoirs kept at different temperatures. Importantly, many observables characterizing operation performance these machines geometric nature.

We study heat rectification through quantum dots in the Coulomb blockade regime using a master equation approach. consider both cases of two-terminal and four-terminal devices. In configuration, we analyze case single dot with either doubly-degenerate level or two non-degenerate levels. sequential tunneling behaviour currents as functions position energy levels temperature bias. particular, derive an upper bound for closed-circuit setup level. also prove absence identify ideal system...

We experimentally realize protocols that allow us to extract work beyond the free energy difference from a single-electron transistor at single thermodynamic trajectory level. With two carefully designed out-of-equilibrium driving cycles featuring kicks of control parameter, we demonstrate extraction up large fractions kBT or with probabilities substantially greater than 1/2, despite zero over cycle. Our results are explained in framework nonequilibrium fluctuation relations. thus show...

Abstract Feedback control of open quantum systems is fundamental importance for practical applications in various contexts, ranging from computation to error correction and metrology. Its use the context thermodynamics further enables study interplay between information energy. However, deriving optimal feedback strategies highly challenging, as it involves systems, stochastic nature measurement, inclusion policies that maximize a long-term time- trajectory-averaged goal. In this work, we...

We present a comprehensive and systematic study of thermal rectification in prototypical low-dimensional quantum system---a nonlinear resonator: we identify necessary conditions to observe discuss strategies maximize it. focus, particular, on the case where anharmonicity is very strong system reduces qubit. In latter case, derive general upper bounds which hold weak system-bath coupling regime, show how Lamb shift can be exploited enhance rectification. then go beyond weak-coupling regime by...

We present a unified approach to study continuous measurement-based quantum thermal machines in static as well adiabatically driven systems. investigate both steady-state and transient dynamics for the time-independent case. In case, we show how thermodynamic quantities can be attributed geometric characteristics. also provide appropriate definition heat transfer dissipation owing measurement presence absence of adiabatic driving. illustrate aforementioned ideas phenomenon refrigeration two...

We investigated coupled-qubit-based thermal machines powered by quantum measurements and feedback. considered two different versions of the machine: (1) a Maxwell's demon, where coupled-qubit system is connected to detachable single shared bath, (2) measurement-assisted refrigerator, in contact with hot cold bath. In demon case, we discuss both discrete continuous measurements. found that power output from qubit-based device can be improved coupling it second qubit. further simultaneous...

The Kerr-cat qubit is a bosonic in which multiphoton Schrödinger cat states are stabilized by applying two-photon drive to an oscillator with Kerr nonlinearity. suppressed bit-flip rate increasing size makes this promising candidate implement quantum error correction codes tailored for noise-biased qubits. However, achieving strong light-matter interactions necessary stabilizing and controlling has traditionally required microwave drives that heat the degrade its performance. In contrast,...

We study the electronic thermal drag in two different Coulomb-coupled systems, first one composed of Coulomb-blockaded metallic islands and second consisting parallel quantum wires. The conductors each system are electrically isolated placed circuits (the drive drag) a four-electrode setup. systems biased, either by temperature $\mathrm{\ensuremath{\Delta}}T$ or voltage $V$ difference, on circuit, while no biases present circuit. In case pair we use master equation approach to determine...

We study the phenomenon of absorption refrigeration, where refrigeration is achieved by heating instead work, in two different setups: a minimal set up based on coupled qubits, and non-linearly resonators. Considering ZZ interaction between we outline basic ingredients required to achieve cooling. Using local as well global master equations, observe that inclusion XX type term qubit-qubit coupling detrimental compare cooling effect obtained qubit case with resonators (multi-level system)...

We consider a finite quantum system under slow driving and weakly coupled to thermal reservoirs at different temperatures. present systematic derivation of the master equation for density matrix out-of-time-order correlators. start from microscopic Hamiltonian we formulate equations ruling dynamics these quantities by recourse Schwinger-Keldysh non-equilibrium Green's function formalism, performing perturbative expansion in coupling between reservoirs. focus on adiabatic dynamics, which...

Introduction The post-coronavirus disease 2019 (COVID-19) syndrome is defined as the persistence of symptoms after viral clearance and emergence new a few months following recovery from COVID-19. This study aimed to assess prevalence post-COVID-19 risk factors that contribute its development. Methods was conducted prospectively in Tribhuvan University Teaching Hospital (TUTH), located Maharajgunj, Kathmandu. patients were followed up for three months. Results post-COVID status 300 admitted...

In a single-qubit weak-measurement-based device, one may imagine feedback control as conducted by quantum Maxwell's demon. Here, the authors investigate both discrete and continuous measurements in such device order to connect work entropy statistics demon's perceived arrow of time.

We perform direct thermovoltage measurements in a single-electron transistor, using on-chip local thermometers, both the linear and nonlinear regimes. Using model which accounts for cotunneling, we find excellent agreement with experimental data no free parameters even when temperature difference is larger than average (far-from-linear regime). This allows us to confirm sensitivity of on cotunneling that regime metallic island crucial parameter. Surprisingly, tends overheat at zero net...

We present a theoretical study of nanowire made three-dimensional topological insulator. The bulk insulator is described by continuum-model Hamiltonian, and the cylindrical-nanowire geometry modelled hard-wall boundary condition. provide secular equation for eigenergies systems (both surface states) analytical form energy eigenfunctions. describe how states cylinder are modified finite-size effects. In particular, we $1/R$ expansion up to second order. knowledge wavefunctions enables...

Dravet syndrome is rare genetic epilepsy and epileptic encephalopathy. The patient initially has normal developmental profile with plateau or regression that begins after seizure onset. We report a case of two-year-old child diagnosed as dravet moderate cerebral atrophy ventricular dilatation MRI finding.

The fundamental trade-off between robustness and tunability is a central challenge in the pursuit of quantum simulation fault-tolerant computation. In particular, many emerging architectures are designed to achieve high coherence at expense having fixed spectra consequently limited types controllable interactions. Here, by adiabatically transforming fixed-frequency superconducting circuits into modifiable Floquet qubits, we demonstrate an XXZ Heisenberg interaction with fully adjustable...

Thermoelectric devices that operate on quantum principles have been under extensive investigation in the past decades. These are at fundamental limits of miniaturized heat engines and refrigerators, advancing field thermodynamics. Most research this area concerns use conduction electrons holes as charge carriers, only very recently superconductors considered thermal thermoelectric devices. Here, we investigate response an Abrikosov vortex type-II deep limit. We consider two geometries, a SIN...

Kerr-cat qubits are bosonic with autonomous protection against bit-flips. They have been studied widely using driven Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL) oscillators. We theoretically investigate an alternate circuit for the qubit, namely Symmetrically Threaded SQUIDs (STS). perform analysis and derive Gorini-Kossakowski-Sudarshan-Lindblad (GKLS) master equation qubit attached to a thermal environment. find that lifetime time of coherent states ($T_\alpha$) is same...

Feedback control of open quantum systems is fundamental importance for practical applications in various contexts, ranging from computation to error correction and metrology. Its use the context thermodynamics further enables study interplay between information energy. However, deriving optimal feedback strategies highly challenging, as it involves systems, stochastic nature measurement, inclusion policies that maximize a long-term time- trajectory-averaged goal. In this work, we employ...

We investigate the thermoelectric response of an Abrikosov vortex in type-II superconductors deep quantum limit. consider two geometries, a superconductor-insulator-normal-metal (S-I-N) junction and local scanning tunneling microscope (STM)-tip normal metal probe over superconductor. exploit strong breaking particle-hole symmetry vortex-bound states at subgap energies within superconducting to realize giant presence fluxons. predict thermovoltage few mV/K subkelvin temperatures using both...

The Kerr-cat qubit is a bosonic in which multi-photon Schrodinger cat states are stabilized by applying two-photon drive to an oscillator with Kerr nonlinearity. suppressed bit-flip rate increasing size makes this promising candidate implement quantum error correction codes tailored for noise-biased qubits. However, achieving strong light-matter interactions necessary stabilizing and controlling has traditionally required microwave drives that heat the degrade its performance. In contrast,...