Algebraic order and the Berezinskii-Kosterlitz-Thouless transition in an exciton-polariton gas

Nitsche, W.; Kim, Na Young; Roumpos, Georgios; Schneider, Christian; Kamp, M.; Höfling, Sven; Forchel, A.; Yamamoto, Yoshihisa

doi:10.1103/physrevb.90.205430

Cited by 72 publications

(64 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, approaching the transition from above by lowering the pump power, the critical value x KT is reached first, and the system loses algebraic order through unbinding of vortices [300][301][302]. On the other hand, the crossover to the disordered regime will be controlled by KPZ physics once x * ≥ x KT , which can be achieved by increasing the loss rate (i.e., reducing the cavity Q) toγ ≈ 0.5.…”

Section: Absence Of Algebraic Order In 2dmentioning

confidence: 99%

“…Both in experiments on incoherently pumped polariton condensates [300,301] and simulations of parametrically pumped systems [302], spatial correlations have been found to decay algebraically within the confines of the system. This, however, is not in contradiction to the present analysis based on the KPZ equation: indeed, if the microscopic value g 0 of the rescaled non-linearity (190) is small, which is actually the case in current experiments [19], a renormalized value of g = 1 is reached in the RG flow only at the exponentially large scale…”

Section: Absence Of Algebraic Order In 2dmentioning

confidence: 99%

See 1 more Smart Citation

Keldysh field theory for driven open quantum systems

2016

View full text Add to dashboard Cite

Recent experimental developments in diverse areas -ranging from cold atomic gases to light-driven semiconductors to microcavity arrays -move systems into the focus which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in equilibrium condensed matter physics. This concerns both their non-thermal stationary states, as well as their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems. CONTENTS

show abstract

Section: Absence Of Algebraic Order In 2dmentioning

confidence: 99%

Section: Absence Of Algebraic Order In 2dmentioning

confidence: 99%

Keldysh field theory for driven open quantum systems

2016

View full text Add to dashboard Cite

show abstract

“…The latter have been intensively investigated in both recent experimental [38][39][40] and theoretical [36,54] works. It has been claimed that polariton systems display a kind of dissipative Berezinskii-Kosterlitz-Thouless (BKT) transition, while critical exponents may differ from the ones obtained in thermal equilibrium [36,[38][39][40]. Here, we assume that the system is sufficiently far away from the critical point on the ordered side of it, so the system converges to an approximately defect-free phase.…”

mentioning

confidence: 99%

Phase ordering kinetics of a nonequilibrium exciton-polariton condensate

Kulczykowski

Matuszewski

2017

Phys. Rev. B

View full text Add to dashboard Cite

We investigate the process of coarsening via annihilation of vortex-antivortex pairs, following the quench to the condensate phase in a nonresonantly pumped polariton system. We find that the late-time dynamics is an example of universal phase-ordering kinetics, characterized by scaling of correlation functions in time. Depending on the parameters of the system, the evolution of the characteristic length scale L(t) can be the same as for the two-dimensional XY model, described by a power law with the dynamical exponent z ≈ 2 and a logarithmic correction, or z ≈ 1 which agrees with previous studies of conservative superfluids.

show abstract

“…The coherence of interacting, equilibrium 2D Bose gases decays with a power law at large distances. The exponent is no greater than 1/4, which is reached at the threshold for the Berezinskii-Kosterlitz-Thouless transition [15]. It is known that the equation of motion for the local phase of a non-equilibrium drivendissipative 2D condensate is in the universality class of the Kardar-Parisi-Zhang (KPZ) equation [16], and nonpower-law decays are possible.…”

mentioning

confidence: 99%

Spatiotemporal coherence of non-equilibrium multimode photon condensates

et al. 2016

View full text Add to dashboard Cite

We report on the observation of quantum coherence of Bose-Einstein condensed photons in an optically pumped, dye-filled microcavity. We find that coherence is long-range in space and time above condensation threshold, but short-range below threshold, compatible with thermalequilibrium theory. Far above threshold, the condensate is no longer at thermal equilibrium and is fragmented over non-degenerate, spatially overlapping modes. A microscopic theory including cavity loss, molecular structure and relaxation shows that this multimode condensation is similar to multimode lasing induced by imperfect gain clamping. BEC means that interferometry is one of the most urgent measurements to be made with a condensate [4,5]. Where thermal equilibrium is not completely reached, coherence is the defining characteristic of non-BEC quantum condensation, e.g for semiconductor exciton-polaritons [6-9] and organic polaritons [10,11]. In nonideal Bose gases, such as ultracold atoms, interactions tend to reduce but not destroy the coherence [12][13][14].The long range coherence behaviour of two-dimensional (2D) microcavity condensates is currently an open question. The coherence of interacting, equilibrium 2D Bose gases decays with a power law at large distances. The exponent is no greater than 1/4, which is reached at the threshold for the Berezinskii-Kosterlitz-Thouless transition [15]. It is known that the equation of motion for the local phase of a non-equilibrium drivendissipative 2D condensate is in the universality class of the Kardar-Parisi-Zhang (KPZ) equation [16], and nonpower-law decays are possible. Since the long-range coherence only shows non-equilibrium behaviour for systems which are very large compared to interaction length scales (such as the healing length), it has proven difficult to observe the true long-range behaviour, mainly due to unavoidable pumping inhomogeneities [17].Photon condensates in dye-filled microcavities are weakly interacting [18][19][20][21], inhomogeneous [22, 23], dissipative Bose gases close to thermal equilibrium at room temperature [24][25][26][27][28]. It is worth noting that the physical system has some similarities to a dye laser, with the decisive difference being that lasing is necessarily a non-equilibrium effect whereas photons can also undergo BEC in thermal equilibrium. Consequently BEC implies macroscopic occupation of the ground state independently of the loss and gain properties, whereas a laser is characterised by a large occupation of exactly the mode that has the most gain [29].Unique among physical realisations of BEC, in dye-microcavity photon BEC the particles thermalise only with a bath and not directly among themselves. This implies that the establishment of phase coherence in the OPEN ACCESS RECEIVED

show abstract

Algebraic order and the Berezinskii-Kosterlitz-Thouless transition in an exciton-polariton gas

Cited by 72 publications

References 35 publications

Keldysh field theory for driven open quantum systems

Keldysh field theory for driven open quantum systems

Phase ordering kinetics of a nonequilibrium exciton-polariton condensate

Spatiotemporal coherence of non-equilibrium multimode photon condensates

Contact Info

Product

Resources

About