Endurance of quantum coherence due to particle indistinguishability in noisy quantum networks

Abstract

Quantum coherence, the physical property underlying fundamental phenomena such as multi-particle interference and entanglement, has emerged as a valuable resource upon which modern technologies are founded. In general, the most prominent adversary of quantum coherence is noise arising from the interaction of the associated dynamical system with its environment. Under certain conditions, however, the existence of noise may drive quantum and classical systems to endure intriguing nontrivial effects. In this vein, here we demonstrate, both theoretically and experimentally, that when two indistinguishable non-interacting particles co-propagate through quantum networks affected by non-dissipative noise, the system always evolves into a steady state in which coherences accounting for particle indistinguishabilty perpetually prevail. Furthermore, we show that the same steady state with surviving quantum coherences is reached even when the initial state exhibits classical correlations. *

Two-particle quantum correlations in stochastically-coupled networks

“…Recently, it has been shown that coherences arising from particle indistinguishability are robust against noise [24,38]. By making use of our model, we have verified that in the steady-state, coherences accounting for particle indistinguishability do survive the impact of stochastic fluctuations in the coupling between sites (see appendix C for details).…”

“…To elucidate the effect of the stochastic coupling between sites, we now compute the dynamics of a single excitation in a fully connected network composed by three sites. We have chosen this configuration, because it constitutes the simplest quantum network that one can investigate both theoretically and experimentally [5,24]. The energies of the sites are arbitrarily chosen to be ω 1 =ω 2 =ω 3 =5 ps −1 , whereas the coupling between them are set to κ 12 =1 ps −1 , and κ 13 =κ 23 =0.5 ps −1 .…”

“…The energies of the sites are arbitrarily chosen to be ω 1 =ω 2 =ω 3 =5 ps −1 , whereas the coupling between them are set to κ 12 =1 ps −1 , and κ 13 =κ 23 =0.5 ps −1 . Figure 1 shows some examples of platforms where single-excitation stochastic networks have been successfully implemented, namely optical tweezers [25], waveguide arrays [24], superconducting circuits [26][27][28], and electrical-circuit arrays [29]. Quite recently, it has been shown that stochastic quantum networks can also be implemented in fascinating platforms, such as nuclear magnetic resonance systems [30], and ion traps [31,32].…”

“…We now turn our attention to the description of two-particle correlation dynamics. To this end, we use the concept of two-particle probability amplitude [24,38], and derive the corresponding equations of motion for finite tight-binding networks comprising N sites.…”

“…We start by noting that the probability amplitudes for a quantum particle, initialized at a site n, are governed by the equations [24,38]:…”