"Spin squeezing via interaction with a driven, dissipative ancillary system"Shane Dooley

Spin squeezing via interaction with a driven,
dissipative ancillary system

Dr. Shane Dooley
National Institute of Informatics, Tokyo

• Date: Tuesday, 27 October
• Time: 11:00-12:00
• Venue: D014, Level D, Lab1

Abstruct:
Abstract: Squeezed states of spin systems are an important entangled resource for quantum technologies, particularly for quantum metrology. Here we consider the generation of spin squeezed states by interacting the spin system with a driven, dissipative ancillary system which, for concreteness, we take to be a superconducting flux qubit. We show that spin squeezing can be generated in this model by two different mechanisms: one-axis twisting and driven collective relaxation; and that we can interpolate between the two mechanisms by simply changing the detuning between the dissipative ancillary system and the spin system. To assess the feasibility of spin squeezing we consider realistic imperfections in the model and we choose some realistic parameters. We conclude that -- with the help of dynamical decoupling -- it is experimentally feasible to generate a squeezed state of hundreds of spins either by one-axis twisting or by driven collective relaxation. Interestingly, for one-axis twisting, the spin squeezing is very robust to ancillary system dissipation and can even be improved by it in some situations.