Two distinguishable impurities in BEC: squeezing and entanglement of two Bose polarons

Abstract

We study entanglement and squeezing of two uncoupled impurities immersed in a Bose-Einstein condensate. We treat them as two quantum Brownian particles interacting with a bath composed of the Bogoliubov modes of the condensate. The Langevin-like quantum stochastic equations derived exhibit memory effects. We study two scenarios: (i) In the absence of an external potential, we observe sudden death of entanglement; (ii) In the presence of an external harmonic potential, entanglement survives even at the asymptotic time limit. Our study considers experimentally tunable parameters.

Bath-Induced Correlations Enhance Thermometry Precision at Low Temperatures

“…We show that these correlations help improving the precision of these experiments and provide strong evidence that they allow beating the shot-noise-limit and even reach a Heisenberglike scaling at low-enough temperatures. Our results can be used to address and improve non-demolition thermometry of Bose-Einstein condensates (BECs) in the nK and sub-nK domain aligned with previous efforts in characterizing correlations in BECs [24].…”

“…We call this phenomenon bath induced correlations. In the past few years, several theoretical works have reported bath induced entanglement in different platforms including Bosonic and Fermionic environments [19][20][21][22][23][24] and even realized them experimentally [25]. However, to our knowledge, the use of such correlations to estimate the bath parameters has never been studied.…”

“…Not only taking them into account is necessary for precise interpretation of the statistics, but also they offer a subshot-noise scaling. The recent results showing the existence of quantum correlations among different impurities embedded in a Bose Einstein condensate (BEC) imply that our scheme is necessary to describe more precisely and comprehensively the thermometry of BEC and other ultracold atomic gases [24]. FIG.…”

Control of anomalous diffusion of a Bose polaron

“…Moreover, we comment that the setup we studied, thanks to the appearance of this gapped subohmic spectral density, could also serve for simulating quantum-optical phenomena, phenomena that could be seen in photonic crystals, with cold atoms, as was proposed also in [83] for the case of optical lattices. In addition, we note that our studies could be extended to the scenario of having two impurities in the coherently coupled two-component BEC, and study as in [37], the effects that the coupling to the spin mode could have on the bath-induced entanglement between the two impurities. Finally, we could also study the effect that this new gapped spectral density could have on the functioning of the impurity as a probe to measure the temperature of the two-component BEC, as in [84].…”

“…In quantum systems, a paradigmatic instance of a highly controlled system is that of a Bose Einstein Condensate (BEC). It was shown that BEC with tunable interactions, are promising systems to study a number of diffusionrelated phenomena, such as Anderson Localization (AL) in disordered media [15][16][17], the expansion of 1D BEC in disordered speckle potentials [15][16][17][18][19][20][21][22][23], the subdiffusive behavior of the expansion of a wave packet of a 1D quantum, chaotic and nonlinear system [15,22,[24][25][26][27][28][29][30][31][32][33], the Brownian motion of solitons in BEC [34], as well as the superdiffusive motion of an impurity in a BEC studied in [35][36][37].…”