



01434nas a2200193   4500008004100000245005500041210005500096260001500151490000800166520090200174100001701076700001601093700001701109700001801126700002101144700001701165700002101182856003701203       2019                        eng d00aPhoton pair condensation by engineered dissipation0 aPhoton pair condensation by engineered dissipation  c04/02/20190 v1233 a<p>Dissipation can usually induce detrimental decoherence in a quantum system. However, engineered dissipation can be used to prepare and stabilize coherent quantum many-body states. Here, we show that by engineering dissipators containing photon pair operators, one can stabilize an exotic dark state, which is a condensate of photon pairs with a phase-nematic order. In this system, the usual superfluid order parameter, i.e. single-photon correlation, is absent, while the photon pair correlation exhibits long-range order. Although the dark state is not unique due to multiple parity sectors, we devise an additional type of dissipators to stabilize the dark state in a particular parity sector via a diffusive annihilation process which obeys Glauber dynamics in an Ising model. Furthermore, we propose an implementation of these photon-pair dissipators in circuit-QED architecture.&nbsp;</p>1 aCian, Ze-Pei1 aZhu, Guanyu1 aChu, Su-Kuan1 aSeif, Alireza1 aDeGottardi, Wade1 aJiang, Liang1 aHafezi, Mohammad  uhttps://arxiv.org/abs/1904.0001601505nas a2200157   4500008004100000245008300041210006900124260001400193490000900207520101200216100001801228700002101246700002201267700002101289856003701310       2018                        eng d00aThermal management and non-reciprocal control of phonon flow via optomechanics0 aThermal management and nonreciprocal control of phonon flow via   c2018/3/230 v9(1)3 a<p>Engineering phonon transport in physical systems is a subject of interest in the study of materials and plays a crucial role in controlling energy and heat transfer. Of particular interest are non-reciprocal phononic systems, which in direct analogy to electric diodes, provide a directional flow of energy. Here, we propose an engineered nanostructured material, in which tunable non-reciprocal phonon transport is achieved through optomechanical coupling. Our scheme relies on breaking time-reversal symmetry by a spatially varying laser drive, which manipulates low-energy acoustic phonons. Furthermore, we take advantage of recent developments in the manipulation of high-energy phonons through controlled scattering mechanisms, such as using alloys and introducing disorder. These combined approaches allow us to design an acoustic isolator and a thermal diode. Our proposed device will have potential impact in phonon-based information processing, and heat management in low temperatures.&nbsp;</p>1 aSeif, Alireza1 aDeGottardi, Wade1 aEsfarjani, Keivan1 aHafezi, Mohammad  uhttps://arxiv.org/abs/1710.08967