"Hybrid systems for the dissipative preparation of mechanical Schrödinger cats"

Context of project
​Realizing the paradigm of a quantum superposition of macroscopic states has notable technological and fundamental implications. Schrödinger cats have not only countless applications in fields like metrology or quantum information, but also brings us closer to answer fundamental questions in quantum mechanics, such as the quantum-to-classical transition and the need of a measurement postulate [1]. Hybrid systems integrated by mechanical oscillators with large Q-factors coupled to another quantum element such as spin qubit offer very intriguing playground for exploring quantum superposition in a macroscopic setup.  

Schrödinger cats and the Quantum∕Classical Boundary ref:
[1] physicstoday.scitation.org/doi/10.1063/1.882326 

Our work
In collaboration with Dr. Carlos Sanchez a theoretical proposal was developed of a novel hybrid system for the generation of nonclassical mechanical states even in the presence of dissipation. In particular, we demonstrate that the implementation of a two-phonon Jaynes-Cummings Hamiltonian under coherent driving of the qubit yields a dissipative phase transition with similarities to the one predicted in the model of the degenerate parametric oscillator:
beyond a certain threshold in the driving amplitude, the driven-dissipative system sustains a mixed steady state consisting of a “jumping cat,” i.e., a cat state undergoing random jumps between two phases. We consider realistic setups and show that, in samples within reach of current technology, the system features nonclassical transient states, characterized by a negative Wigner function, that persist during timescales of fractions of a second.

Read more:
​Hybrid systems for the generation of nonclassical mechanical states via quadratic interactions
C.S. Muñoz, A. Lara, J. Puebla, F. Nori
Physical review letters 121 (12), 123604 (2018) 
journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.123604
arXiv: arxiv.org/abs/1802.01306    
Personal contribution: Proposed project, provided advice in experimental scheme and figures of merit