Constructing an entangled Unruh Otto engine and its efficiency

Abstract

Uniformly accelerated frame mimics a thermal bath whose temperature is proportional to the proper acceleration. Using this phenomenon we give a detailed construction of an Otto cycle between two energy eigenstates of a system, consists of two entangled qubits. In the isochoric stages the thermal bath is being provided via the vacuum fluctuations of the background field for a monopole interaction by accelerating them. We find that making of Otto cycle is possible when one qubit is accelerating in the right Rindler wedge and other one is moving in the left Rindler wedge; i.e. in anti-parallel motion, with the initial composite state is a non-maximally entangled one. However, the efficiency greater than that of the usual single qubit quantum Otto engine is not possible. We provide values of the available parameters which make Otto cycle possible. On the other hand, Otto cycle is not possible if one considers the non-maximally entangled state for parallel motion. Moreover, for both initial symmetric and anti-symmetric Bell states we do not find any possibility of the cycle for qubits’ parallel and anti-parallel motion.

Accelerated paths and Unruh effect: finite time detector response in (anti) de Sitter spacetime and Huygen’s principle

“…The variation of response function in dS and AdS space with respect to curvature makes the situation quite interesting and we are focusing on explicit conditions to extract required conditions for completing Otto cycle to have positive work output. The recent claim that with entangled qubits one can build up more efficient [38,39] Otto engine is quite exciting and we are exploring the possibility to generalise it with maximally symemtric spacetimes. In our current manuscript, we have worked with scalar theory which is conformally coupled to background gravity but we are in a process of computing the finite time response function of UDW detectors for minimally coupled scalar theory.…”

Relativistic quantum Otto engine: instant work extraction from a quantum field

“…A perturbative analysis of QOE utilizing a UDW detector was investigated in [25] (see [17,18,[21][22][23][24] for analyses involving a linearly accelerating UDW detector). In these scenarios, a pointlike (i.e., zero-size) UDW detector interacts with a quasi-free state over a finite time duration.…”

“…Such a QOE driven by the Unruh effect is particularly called the Unruh QOE. See also [21][22][23][24] for subsequent studies. The Unruh QOE concept extends to scenarios where a UDW detector follows an arbitrary timelike trajectory in curved spacetime [25].…”

Quantum Otto engine driven by quantum fields

“…The amount of work extracted is determined by a response function of the UDW detector, which is the probability of a transition from the ground state to the excited state and vice versa. Subsequent studies have further expanded on the Unruh QOE in various scenarios, including a fermionic field [14], a degenerate detector [15], entangled detectors [16,17], and in the presence of a reflecting boundary [18]. However, these studies focus on a specific acceleration trajectory, the state of a field, and a switching function.…”