Autonomous quantum refrigerator in a circuit QED architecture based on a Josephson junction

Hofer, Patrick P.; Perarnau-Llobet, Martí; Brask, Jonatan Bohr; Silva, Ralph; Huber, Marcus; Brunner, Nicolás

doi:10.1103/physrevb.94.235420

Cited by 130 publications

(110 citation statements)

References 42 publications

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“…The CI and Eq. (A2) both reduce to P k β k q k ≥ 0 in two important cases: (1) when there is no mediating system (e.g., in absorption refrigerators with a tricycle interaction [12,47]) and (2) in (quasi)stationary periodic operation of a heat machine interacting with a large bath, where ΔhB sys i is negligible with respect to the accumulated heat exchanges.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Global Passivity in Microscopic Thermodynamics

Uzdin

Rahav

2018

Phys. Rev. X

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The main thread that links classical thermodynamics and the thermodynamics of small quantum systems is the celebrated Clausius inequality form of the second law. However, its application to small quantum systems suffers from two cardinal problems. (i) The Clausius inequality does not hold when the system and environment are initially correlated-a commonly encountered scenario in microscopic setups. (ii) In some other cases, the Clausius inequality does not provide any useful information (e.g., in dephasing scenarios). We address these deficiencies by developing the notion of global passivity and employing it as a tool for deriving thermodynamic inequalities on observables. For initially uncorrelated thermal environments the global passivity framework recovers the Clausius inequality. More generally, global passivity provides an extension of the Clausius inequality that holds even in the presences of strong initial system-environment correlations. Crucially, the present framework provides additional thermodynamic bounds on expectation values. To illustrate the role of the additional bounds, we use them to detect unaccounted heat leaks and weak feedback operations ("Maxwell demons") that the Clausius inequality cannot detect. In addition, it is shown that global passivity can put practical upper and lower bounds on the buildup of system-environment correlations for dephasing interactions. Our findings are highly relevant for experiments in various systems such as ion traps, superconducting circuits, atoms in optical cavities, and more.

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Section: Acknowledgmentsmentioning

confidence: 99%

Global Passivity in Microscopic Thermodynamics

Uzdin

Rahav

2018

Phys. Rev. X

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confidence: 99%

“…To make the characterization complete, we also measure the entropy and energy of the system and the demon. Superconducting circuits thus reveal themselves as a suitable experimental testbed for the blooming field of quantum thermodynamics of information (15)(16)(17)(18)(19).In the experiment, the system S is a transmon superconducting qubit (20) with energy difference hfS = h × 7.09 GHz between its ground |g and excited |e states. It is embedded in a microwave cavity that resonates at fD = 7.91 GHz and plays the role of the demon's memory D. The dispersive Hamiltonian reads H = hfS |e e|S + hfD d † d − hχd † d |e e|S , where d is the annihilation operator of a photon in the cavity.…”

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confidence: 99%

Observing a quantum Maxwell demon at work

Cottet

Jezouin

Bretheau

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

236

187

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In apparent contradiction to the laws of thermodynamics, Maxwell's demon is able to cyclically extract work from a system in contact with a thermal bath, exploiting the information about its microstate. The resolution of this paradox required the insight that an intimate relationship exists between information and thermodynamics. Here, we realize a Maxwell demon experiment that tracks the state of each constituent in both the classical and quantum regimes. The demon is a microwave cavity that encodes quantum information about a superconducting qubit and converts information into work by powering up a propagating microwave pulse by stimulated emission. Thanks to the high level of control of superconducting circuits, we directly measure the extracted work and quantify the entropy remaining in the demon's memory. This experiment provides an enlightening illustration of the interplay of thermodynamics with quantum information.quantum thermodynamics | superconducting circuits | quantum information I n 1867, pondering the newly developed thermodynamic laws, Maxwell came to the disturbing conclusion that a "demon" can extract work cyclically from a thermodynamic system beyond the limits set by the second law when acting upon the information it obtains about the system (1). This paradox was resolved a century later when Landauer realized that information processing has an entropic cost and Bennett argued that the demon's memory must take full part in the thermodynamic cycle (2). Recent experiments have realized classical versions of elementary Maxwell demons in various physical systems (3-8). Although quantum versions have long been investigated theoretically (9-13), experimental realizations are in their infancy (7,8), and a full characterization is still missing. Using superconducting circuits, we reveal the inner mechanics of a quantum Maxwell demon that is able to extract work from a quantum system. Importantly, we are able to directly probe the extracted work by measuring the output power emitted by the system through stimulated emission, without inferring it from system trajectories (3-6, 14). We are thus able to demonstrate how the information stored in the demon's memory affects the extracted work. To make the characterization complete, we also measure the entropy and energy of the system and the demon. Superconducting circuits thus reveal themselves as a suitable experimental testbed for the blooming field of quantum thermodynamics of information (15)(16)(17)(18)(19).In the experiment, the system S is a transmon superconducting qubit (20) with energy difference hfS = h × 7.09 GHz between its ground |g and excited |e states. It is embedded in a microwave cavity that resonates at fD = 7.91 GHz and plays the role of the demon's memory D. The dispersive Hamiltonian reads H = hfS |e e|S + hfD d † d − hχd † d |e e|S , where d is the annihilation operator of a photon in the cavity. The last term induces a frequency shift of the cavity by −χ = −33 MHz when the qubit is excited. Reciprocally, the qubit frequency is shif...

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“…Mesoscopic refrigerators based on this effect make use of semiconductor quantum dots 7,8 , superconducting-insulator-normal metal (SIN) junctions [9][10][11][12] , or single-electron transistors (SET) 13,14 . Cooling mediated by the coupling to cavity photons has also been proposed in Josephson junctions [15][16][17] and implemented for the refrigeration of metallic islands [18][19][20][21][22] . Here an alternative approach is proposed based on the capacitive coupling of a two-terminal SINIS SET to the system to be cooled, see Fig.…”

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confidence: 99%

Correlation-induced refrigeration with superconducting single-electron transistors

Sánchez

2017

Applied Physics Letters

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A model of a superconducting tunnel junction which refrigerates a nearby metallic island without any particle exchange is presented. Heat extraction is mediated by charge fluctuations in the coupling capacitance of the two systems. The interplay of Coulomb interaction and the superconducting gap reduces the power consumption of the refrigerator. The island is predicted to be cooled from lattice temperatures of 200 mK down to close to 50 mK, for realistic parameters. The results emphasize the role of non-equilibrium correlations in bipartite mesoscopic conductors. This mechanism can be applied to create local temperature gradients in tunnel junction arrays or explore the role of interactions in the thermalization of non-equilibrium systems.Quantum coherent processes relevant to quantum information or quantum thermodynamics 1 are usually damaged by temperature. Solid state quantum simulators 2 or heat engines 3,4 have recently been proposed that operate at very low temperatures. Finding ways to cool nanoscale systems 5,6 , or introduce local temperature gradients well below 100 mK without injecting charge into them is hence a demanding task. This way they are minimally perturbed and not affected by Joule heating.Thermoelectric refrigeration is traditionally based on the Peltier effect. Driving a current through a conductor with broken electron-hole symmetry converts thermal excitations into transport. Mesoscopic refrigerators based on this effect make use of semiconductor quantum dots 7,8 , superconducting-insulator-normal metal (SIN) junctions 9-12 , or single-electron transistors (SET) 13,14 . Cooling mediated by the coupling to cavity photons has also been proposed in Josephson junctions 15-17 and implemented for the refrigeration of metallic islands [18][19][20][21][22] . Here an alternative approach is proposed based on the capacitive coupling of a two-terminal SINIS SET to the system to be cooled, see Fig. 1. We consider cooling of a single-electron box (SEB) 23,24 : a Coulomb blockade island which exchanges electrons with a third terminal. The extraction of energy is mediated by the Coulomb repulsion of electrons in different islands, J. The superconducting gap, ∆, acts as an energy filter: At subgap voltages, only transitions that take energy from from the capacitor contribute to transport. A normal metal SET would unavoidably emit Joule heat at all voltages into the island. The manipulation of electrical and thermal flows in capacitively coupled normal metal or semiconductor systems has been recently demonstrated, including effects such as quantum dot heat engines 25-32 , autonomous Maxwell's demon operations 33,34 , thermal rectifiers 35-37 , memristors 38 , or single-electron current switches 39-41 . The interplay of the two relevant energy scales, J and ∆, in the cooling mechanism is investigated. Subgap transport in the SET is assisted by the Coulomb interaction, hence increasing the voltage window where cooling takes place. Hot electrons in the SET island are thus pumped over the gap of the supercond...

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Autonomous quantum refrigerator in a circuit QED architecture based on a Josephson junction

Cited by 130 publications

References 42 publications

Global Passivity in Microscopic Thermodynamics

Global Passivity in Microscopic Thermodynamics

Observing a quantum Maxwell demon at work

Correlation-induced refrigeration with superconducting single-electron transistors

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