Quantum dissipative systems

A non-classical laser

Lasers are well known to emit coherent states of light. These are to a good approximation classical monochromatic waves. We have shown that by using quantum simulation techniques, a single qubit coupled to a cavitiy can emit laser light in a non-classical "squeezed" state. We have considered a superconducting qubit coupled to a microwave cavity, but our ideas can be extended to many cavities, or even other spin-boson setups (e.g., trapped ion phonon lasers or single atoms coupled to optical cavities).
C. Navarrete-Benlloch, J.J. Garcia-Ripoll, D. Porras, Phys. Rev. Letts. 113, 193601 (2014).

Interesting dark states

Dissipation always had a bad reputation in quantum information processing. Usually it leads to boring, uninteresting (dark) quantum states. However, by controlling the coupling of a quantum system to a dissipative bath, one can induce the generation of entanglement and quantum correlations. We have shown that a mesoscopic ensemble of quantum dots can be led to a spin-squeezed state by a superradiant decay process.  Also, we have shown how to apply dissipation to generate chiral states and squeezed states or propagating quantum fields.
​A. Gonzalez-Tudela and D. Porras, Physical Review Letters 110,  080502 (2013).
D. Porras and J.J. Garcia-Ripoll, Physical Review Letters 108,  043602 (2012).