Description
Initially considered in the context of solid helium, the exotic supersolid phase is characterized by the spontaneous breaking of gauge and spatial translation symmetries. This implies acquiring the phase coherence of a superfluid and the crystalline structure of a solid. The long-sought regime has been recently observed for cavity-coupled atomic systems [1], dipolar gases [2-4] and spin-orbit coupled [5,6] (SOC) systems. Although evidence of supersolidity was shown for the latter, further exploration is hindered by the low contrast of the density modulation and its fragility.
Here, we present theoretical and experimental results on the exploration of the supersolid phase in a $^{39}$K spin-orbit coupled Bose Einstein condensate. We show that the stripe phase becomes more stable than in state-of-the-art experiments in rubidium. The reason is that the atomic interactions of the two-component condensate can be modified to be weakly attractive (miscible), favouring the striped regime. Thanks to the high contrast of the density modulation, the supersolid phase has a peculiar excitation spectrum manifested in the strong modification of the collective modes [7], which we numerically investigate for realistic parameters. Moreover, we present our experimental strategy to directly observe the density modulation of the supersolid in our system by increasing the imaging resolution using matter-wave lensing. This work aims to explore the differences and similarities between the SOC supersolid and realizations in other systems, highlighting the inherent features of a supersolid and the characteristics of each system.
[1] J. Léonard, et al., Nature 543, 87 (2017)
[2] L. Tanzi, et al., Phys. Rev. Lett. 122 130405 (2019)
[3] F. Böttcher, et al., Phys. Rev. X 9 011051 (2019)
[4] L. Chomaz et al., Phys. Rev. X 9 021012 (2019)
[5] J. R. Li, et al., Nature, 543, 91 (2017)
[6] A. Putra, et al., Phys. Rev. Lett., 124, 053605 (2020)
[7] K. T. Geier, et al., Phys. Rev. Lett. 127, 115301 (2021)
Presenter name | Ramon Ramos |
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