Excitation injector in an atomic chain: Long-range transport and efficiency amplification

Doyeux, Pierre; Messina, Riccardo; Leggio, Bruno; Antezza, Mauro

doi:10.1103/physreva.95.012138

Cited by 12 publications

(9 citation statements)

References 34 publications

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“…The relevant point to highlight from these results is that the sign of the ò 2 -terms in equations (11) and (12) will depend on the relative magnitudes of n 1 and n 2 and not of T 1 and T 2 . This simple fact, when combined with the definition of n i in equation (6), introduces several properties which, at first sight, seem to violate the second law of thermodynamics. First, it implies that oscillator 1 can be cooled to a temperature smaller than the temperature T 1 of the coldest reservoir, in the sense that it could reach a state with lower energy than that of the thermal state it would reach if it were in contact only with the coldest reservoir.…”

Section: Predictions For the Steady-statementioning

confidence: 99%

Reconciliation of quantum local master equations with thermodynamics

et al. 2018

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The study of open quantum systems often relies on approximate master equations derived under the assumptions of weak coupling to the environment. However when the system is made of several interacting subsystems such a derivation is in many cases very hard. An alternative method, employed especially in the modeling of transport in mesoscopic systems, consists in using local master equations (LMEs) containing Lindblad operators acting locally only on the corresponding subsystem. It has been shown that this approach however generates inconsistencies with the laws of thermodynamics. In this paper we demonstrate that using a microscopic model of LMEs based on repeated collisions all thermodynamic inconsistencies can be resolved by correctly taking into account the breaking of global detailed balance related to the work cost of maintaining the collisions. We provide examples based on a chain of quantum harmonic oscillators whose ends are connected to thermal reservoirs at different temperatures. We prove that this system behaves precisely as a quantum heat engine or refrigerator, with properties that are fully consistent with basic thermodynamics. derivations are in general quite involved since they require knowledge of the full set of eigenvalues and eigenvectors of the system's Hamiltonian, something which quickly becomes prohibitive when the number of subsystems increases. Moreover, depending on the approximations employed, one may also arrive at equations which do not generate completely positive maps (the so-called Redfield equations [50]), or equations which contain unphysical heat currents [54]. For these reasons, microscopic derivations of master equations for systems connected to multiple environments still continues, nowadays, to be a topic of great interest.An alternative, more heuristic, approach consists in deriving a master equation for the individual subsystems, neglecting the interaction with the remaining subsystems. The resulting master equation will then contain only local jump operators describing exchanges between the environment E i and its corresponding subsystem S i . Such equations, which we shall henceforth refer to as LMEs (also frequently called boundarydriven master equations), are typically accurate when the dissipation rates are larger than the interaction between subsystems. Due to their computational simplicity, they have been extensively employed over the last two decades in the study of transport in non-equilibrium quantum systems [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73].It turns out, however, that the nonlocal terms neglected in the LME may still lead to non-thermal steadystates [74] and play a significant role if the heat exchanges are small, even for weakly interacting parts. As a consequence, it has been found that LMEs may lead to apparent thermodynamic inconsistencies, as pointed out recently by Levy and Kosloff [75]. They have shown that the LME for two coupled quantum harmonic oscillators (QHO) may predict currents from a cold to a hot ther...

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Section: Predictions For the Steady-statementioning

confidence: 99%

Reconciliation of quantum local master equations with thermodynamics

et al. 2018

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“…Super-and subradiance have been observed experimentally not only in atomic gases, but also in QED circuits [22,23], metamaterial arrays [24], and quantum dots [25][26][27]. This collective atom-light coupling has found a variety of applications such as storage of light via the preparation of subradiant states through phase-imprinting protocols [28][29][30][31][32][33][34][35][36][37][38], topologically protected transport of excitations [39,40], or efficient long-range energy transport [41][42][43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Subradiance-protected excitation transport

2019

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We explore excitation transport within a one-dimensional chain of atoms where the atomic transition dipoles are coupled to the free radiation field. When the atoms are separated by distances smaller or comparable to the wavelength of the transition, the exchange of virtual photons leads to the transport of the excitation through the lattice. Even though this is a strongly dissipative system, we find that the transport is subradiant, that is, the excitation lifetime is orders of magnitude longer than the one of an individual atom. In particular, we show that a subspace of the spectrum is formed by subradiant states with a linear dispersion relation, which allows for the dispersionless transport of wave packets over long distances with virtually zero decay rate. Moreover, the group velocity and direction of the transport can be controlled via an external uniform magnetic field while preserving its subradiant character. The simplicity and versatility of this system, together with the robustness of subradiance against disorder, makes it relevant for a range of applications such as lossless energy transport and long-time light storage.

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“…Focusing on the microscopic scale, one can cite the well-known example of photosynthesis, a natural process in which light is harvested across chromophore complexes from the absorption to the reaction center. On a fundamental level, many efforts have been devoted to unveil the mechanisms at the origin of the efficient energy transport within open quantum systems [1][2][3][4][5][6][7][8][9].…”

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confidence: 99%

Giant Interatomic Energy-Transport Amplification with Nonreciprocal Photonic Topological Insulators

et al. 2017

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We show that the energy-transport efficiency in a chain of two-level emitters can be drastically enhanced by the presence of a photonic topological insulator (PTI). This is obtained by exploiting the peculiar properties of its nonreciprocal surface plasmon polariton (SPP), which is unidirectional, and immune to backscattering, and propagates in the bulk band gap. This amplification of transport efficiency can be as much as 2 orders of magnitude with respect to reciprocal SPPs. Moreover, we demonstrate that despite the presence of considerable imperfections at the interface of the PTI, the efficiency of the SPP-assisted energy transport is almost unaffected by discontinuities. We also show that the SPP properties allow energy transport over considerably much larger distances than in the reciprocal case, and we point out a particularly simple way to tune the transport. Finally, we analyze the specific case of a two-emitter chain and unveil the origin of the efficiency amplification. The efficiency amplification and the practical advantages highlighted in this work might be particularly useful in the development of new devices intended to manage energy at the atomic scale.

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Excitation injector in an atomic chain: Long-range transport and efficiency amplification

Cited by 12 publications

References 34 publications

Reconciliation of quantum local master equations with thermodynamics

Reconciliation of quantum local master equations with thermodynamics

Subradiance-protected excitation transport

Giant Interatomic Energy-Transport Amplification with Nonreciprocal Photonic Topological Insulators

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