It is generally accepted that quantized vortices formed in coherent bosonic fluids are “excitations” and as such do not arise in a one-mode condensate at zero temperature. To excite them, one needs either inhomogeneities (impurities, rotation, etc.) or essentially finite fluctuations. Here, we predict a perfectly spontaneous formation of vortices even at zero temperature, which takes place in a homogeneous cavity-polariton system under one-mode optical excitation at normal incidence. In spite of the absence of equilibrium and U(1) invariance, this system shows a counterpart of the Berezinskii-Kosterlitz-Thouless crossover between single vortices and coupled vortex-antivortex states ranging from small dipoles to rectilinear filaments with long-range ordering.

中文翻译：

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相干驱动下自旋极化子流体中涡旋和灰孤子的自发形成

人们普遍认为，在相干的玻色子流体中形成的量化涡旋是“激发”，因此不会在零温度下的单模冷凝物中产生。为了激发它们，要么需要不均匀性（杂质，旋转等），要么本质上是有限的波动。在这里，我们预测即使在零温度下，涡流也会自然而然地自然形成，这是在均匀入射光在单模光激发下的均匀腔极化系统中发生的。尽管没有平衡和U（1）不变性，该系统仍显示了Berezinskii-Kosterlitz-Thouless交叉的对应物，该交叉在单个涡旋和耦合的涡旋-反涡旋状态之间变化，从小偶极子到具有长程有序的直线灯丝。