Abstract
We describe and quantify the emergence of coherence between quantum systems that are initially at thermal equilibrium. We show that the coherence can be induced by a conditional locking method based on a feasible joint detection of photons spontaneously emitted by the systems. The energy employed by the locking method comes solely from the initial thermal excitation of the systems, which makes the method suitable for a wide range of experimental platforms. We show that the same method can be applied to a pair of two-level systems or to a pair of quantum oscillators and we compare the results with regard to their first- and second-order correlation functions. We also propose feasible experimental tests to verify the thermally induced coherence.
- Received 23 September 2013
- Revised 22 July 2014
DOI:https://doi.org/10.1103/PhysRevA.90.063820
©2014 American Physical Society