



01834nas a2200157   4500008004100000245007600041210006900117260001400186520133100200100002901531700001601560700002501576700002101601700001701622856003701639       2021                        eng d00aSingularities in nearly-uniform 1D condensates due to quantum diffusion0 aSingularities in nearlyuniform 1D condensates due to quantum dif  c3/10/20213 a<p>Dissipative systems can often exhibit wavelength-dependent loss rates. One prominent example is Rydberg polaritons formed by electromagnetically-induced transparency, which have long been a leading candidate for studying the physics of interacting photons and also hold promise as a platform for quantum information. In this system, dissipation is in the form of quantum diffusion, i.e., proportional to k2 (k being the wavevector) and vanishing at long wavelengths as k&rarr;0. Here, we show that one-dimensional condensates subject to this type of loss are unstable to long-wavelength density fluctuations in an unusual manner: after a prolonged period in which the condensate appears to relax to a uniform state, local depleted regions quickly form and spread ballistically throughout the system. We connect this behavior to the leading-order equation for the nearly-uniform condensate -- a dispersive analogue to the Kardar-Parisi-Zhang (KPZ) equation -- which develops singularities in finite time. Furthermore, we show that the wavefronts of the depleted regions are described by purely dissipative solitons within a pair of hydrodynamic equations, with no counterpart in lossless condensates. We close by discussing conditions under which such singularities and the resulting solitons can be physically realized.</p>1 aBaldwin, Christopher, L.1 aBienias, P.1 aGorshkov, Alexey, V.1 aGullans, Michael1 aMaghrebi, M.  uhttps://arxiv.org/abs/2103.06293