Anti-Unruh phenomena

Abstract

We find that a uniformly accelerated particle detector coupled to the vacuum can cool down as its acceleration increases, due to relativistic effects. We show that in (1+1)-dimensions, a detector coupled to the scalar field vacuum for finite timescales (but long enough to satisfy the KMS condition) has a KMS temperature that decreases with acceleration, in certain regimes. This contrasts with the heating that one would expect from the Unruh effect.

Characterization of Unruh channel in the context of open quantum systems

“…These enable a deeper understanding as well as provide a statistical interpretation [9] for the well known effects such as the Unruh [10,11], Hawking [12], and GibbonsHawking [13] effects. Interestingly, in recent times, finite time aspects of the Unruh effect have revealed an inverse relation between the acceleration and the temperature, a phenomenon known as the anti-Unruh effect [14,15]. This sets the scene for the present work where the ideas of open quantum systems and quantum foundations are used to provide a common platform to address the above problems.…”

Would quantum entanglement be increased by anti-Unruh effect?

“…However, it is found recently that a particle detector in uniform acceleration coupled to the vacuum can cool down with increasing acceleration under certain conditions. This scenario is opposite to that gives the celebrated Unruh effect, and has been appropriately named the anti-Unruh effect [4]. This initial discussion was based on a point-like two-level system and the transition probability was found to decrease with increasing acceleration rather than the expected nominal increasing dependence.…”

“…Although the initial calculation is made in Ref. [4] for accelerated detectors coupled to a massless scalar field either in a periodic cavity or under a hard-IR momentum cutoff for the continuum, it is also showed to represent a general stationary mechanism that remains stable under the disturbance of additional conditions, instead of being a sheer transient phenomenon [5]. Thus, like the Unruh effect, the anti-Unruh effect constitutes a significant breakthrough in our understanding.…”

“…Since the anti-Unruh effect can exist under a stationary state satisfying Kubo-Martin-Schwinger (KMS) condition [6][7][8] and is independent on any kind of boundary * Electronic address: zhangbc.zhang@yahoo.com conditions [4,5], what is its difference from Unruh effect? Although the physically essential reasons remain to be explored, some important elements, like the interaction time, the detector's energy gap, the mass of the quantum field, etc, had been discussed carefully to distinguish the two situations in the earlier works [4,5]. For example, the anti-Unruh effect could appear when the interaction timescale is far away from the timescale associated to the reciprocal of the detector's energy gap.…”

Zero mode suppression of superluminal signals in light-matter interactions

“…In some contexts, such as UDW model coupled via derivative coupling, its effect can indeed be made negligible at the level of detector responses in appropriate limits [16], but in some other contexts it has significant impact on detector dynamics and entanglement [16,17,23,24]. There are also cases when the zero mode has been excluded by assumption from a setup with periodic boundary conditions (e.g., in [25][26][27][28][29]), thus it is of interest to further study the impact that the removal of the zero mode may have on the relativistic nature of the interaction, and in particular in the causality of the whole particle detector model.…”