Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 56: Quantum Optics III

Q 56.5: Talk

Thursday, March 14, 2019, 15:15–15:30, S Ex 04 E-Tech

Revealing the nature of a non-equilibrium phase transition with quantum trajectories — •Valentin Link, Kimmo Luoma, and Walter T. Strunz — Technische Universität Dresden, 01069 Dresden, Germanyy

We consider a quantum master equation of Lindblad type, describing a collectively driven and damped ensemble of spins. Upon changing the drive strength, this model features a second order phase transition in the thermodynamic limit, in the sense that the steady state of the master equation undergoes a non-analytic change. The physical properties of both phases can be intuitively understood in a quantum trajectory picture. In fact, for this particular model, the quantum evolution can be mapped to classical noisy trajectories on a sphere. This helps to identify a spontaneously broken symmetry. In addition, the framework allows to account for finite size effects.