Symmetry-breaking transitions are a well-understood phenomenon of closed quantum systems in quantum optics, condensed matter, and high energy physics. However, symmetry breaking in open systems is less thoroughly understood, in part due to the richer steady-state and symmetry structure that such systems possess. For the prototypical open system{\textemdash}a Lindbladian{\textemdash}a unitary symmetry can be imposed in a {\textquotedblleft}weak{\textquotedblright} or a {\textquotedblleft}strong{\textquotedblright} way. We characterize the possible\ Zn\ symmetry-breaking transitions for both cases. In the case of\ Z2, a weak-symmetry-broken phase guarantees at most a classical bit steady-state structure, while a strong-symmetry-broken phase admits a partially protected steady-state qubit. Viewing photonic cat qubits through the lens of strong-symmetry breaking, we show how to dynamically recover the logical information after any gap-preserving strong-symmetric error; such recovery becomes perfect exponentially quickly in the number of photons. Our study forges a connection between driven-dissipative phase transitions and error correction.

}, doi = {10.1103/PhysRevLett.125.240405}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.125.240405}, author = {Lieu, Simon and Belyansky, Ron and Young, Jeremy T. and Lundgren, Rex and Albert, Victor V. and Gorshkov, Alexey V.} } @article { ISI:000498063400002, title = {Nondestructive Cooling of an Atomic Quantum Register via State-Insensitive Rydberg Interactions}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {21}, year = {2019}, month = {NOV 20}, pages = {213603}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We propose a protocol for sympathetically cooling neutral atoms without destroying the quantum information stored in their internal states. This is achieved by designing state-insensitive Rydberg interactions between the data-carrying atoms and cold auxiliary atoms. The resulting interactions give rise to an effective phonon coupling, which leads to the transfer of heat from the data atoms to the auxiliary atoms, where the latter can be cooled by conventional methods. This can be used to extend the lifetime of quantum storage based on neutral atoms and can have applications for long quantum computations. The protocol can also be modified to realize state-insensitive interactions between the data and the auxiliary atoms but tunable and nontrivial interactions among the data atoms, allowing one to simultaneously cool and simulate a quantum spin model.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.213603}, author = {Belyansky, Ron and Young, Jeremy T. and Bienias, Przemyslaw and Eldredge, Zachary and Kaufman, Adam M. and Zoller, Peter and Gorshkov, V, Alexey} } @article {ISI:000426249900005, title = {Dissipation-induced dipole blockade and antiblockade in driven Rydberg systems}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {2}, year = {2018}, month = {FEB 28}, pages = {023424}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study theoretically and experimentally the competing blockade and antiblockade effects induced by spontaneously generated contaminant Rydberg atoms in driven Rydberg systems. These contaminant atoms provide a source of strong dipole-dipole interactions and play a crucial role in the system{\textquoteright}s behavior. We study this problem theoretically using two different approaches. The first is a cumulant expansion approximation, in which we ignore third-order and higher connected correlations. Using this approach for the case of resonant drive, a many-body blockade radius picture arises, and we find qualitative agreement with previous experimental results. We further predict that as the atomic density is increased, the Rydberg population{\textquoteright}s dependence on Rabi frequency will transition from quadratic to linear dependence at lower Rabi frequencies. We study this behavior experimentally by observing this crossover at two different atomic densities. We confirm that the larger density system has a smaller crossover Rabi frequency than the smaller density system. The second theoretical approach is a set of phenomenological inhomogeneous rate equations. We compare the results of our rate-equation model to the experimental observations {[}E. A. Goldschmidt et al., Phys. Rev. Lett. 116, 113001 (2016)] and find that these rate equations provide quantitatively good scaling behavior of the steady-state Rydberg population for both resonant and off-resonant drives.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.023424}, author = {Young, Jeremy T. and Boulier, Thomas and Magnan, Eric and Goldschmidt, Elizabeth A. and Wilson, Ryan M. and Rolston, Steven L. and Porto, James V. and Gorshkov, Alexey V.} } @article { ISI:000413663300001, title = {Fast Quantum State Transfer and Entanglement Renormalization Using Long-Range Interactions}, journal = {PHYSICAL REVIEW LETTERS}, volume = {119}, number = {17}, year = {2017}, month = {OCT 25}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.119.170503}, author = {Eldredge, Zachary and Gong, Zhe-Xuan and Young, Jeremy T. and Moosavian, Ali Hamed and Foss-Feig, Michael and Gorshkov, Alexey V.} } @article { ISI:000414424700002, title = {Solvable Family of Driven-Dissipative Many-Body Systems}, journal = {PHYSICAL REVIEW LETTERS}, volume = {119}, number = {19}, year = {2017}, month = {NOV 6}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.119.190402}, author = {Foss-Feig, Michael and Young, Jeremy T. and Albert, Victor V. and Gorshkov, Alexey V. and Maghrebi, Mohammad F.} }