On optimal currents of indistinguishable particles

Abstract

We establish a mathematically rigorous, general and quantitative framework to describe currents of non-(or weakly) interacting, indistinguishable particles driven far from equilibrium. We derive tight upper and lower bounds for the achievable fermionic and bosonic steady state current, respectively, which can serve as benchmarks for special cases of interacting many-particle dynamics. For fermionic currents, we identify a symmetry-induced enhancement mechanism in parameter regimes where the coupling between system and reservoirs is weak. This mechanism is broadly applicable provided the inter-particle interaction strength is small as compared to typical exchange interactions.

Scattering theory of efficient quantum transport across finite networks

“…Shown are three different values of the width of the distribution of energy shifts, relative to the input-output coupling,σ = σ/2V . The parameters0 = s0/2V is set to zero, which is consistent with the dominant doublet condition (9,32). Figure obtained from [35].…”

“…In a next step, we rely on earlier results which identified centrosymmetric [29][30][31][32][33][34] random networks as more efficient than unconstrained random assemblies, and specify our scattering model as given by centrosymmetric Hamiltonians of the form…”

“…With the additional choice Γ = Γ [32], H eff becomes a non-Hermitian centrosymmetric matrix. However, centrosymmetry alone is not yet sufficient to guarantee efficient transport features of the networks, as illustrated in Figs.…”

Mode-dependent-loss model for multimode photon-subtracted states

“…As there is no preferred basis, we can again choose to treat the problem in the vertex basis to gain physical insight. We can interpret the losses as a combination of single-mode loss channels, which is essentially what we mathematically achieve through (52). In this sense, we just repeat the scenario of Fig.…”

“…where γ j denotes the loss parameter of the mode h j , that multiplies the overall strength of the losses ξ. Our method to analytically solve equation (10), and obtain the loss channel Λ ξ , is based on earlier work [37] that was explicitly adapted for the bosonic case in [51,52]. There, the general result for the action of Λ ξ on a normally ordered monomial of creation and annihilation operators is given:…”