Publications Lauritz KLAUS

2022

Articles

• L. Klaus, T. Bland, E. Poli, C. Politi, G. Lamporesi, E. Casotti, R. N. Bisset, M. J. Mark, F. Ferlaino Observation of vortices and vortex stripes in a dipolar condensate, Nature Phys. 18 1458 (2022-10-31), http://dx.doi.org/10.1038/s41567-022-01793-8 doi:10.1038/s41567-022-01793-8 (ID: 720846)
• M. Norcia, E. Poli, C. Politi, L. Klaus, T. Bland, M. J. Mark, L. Santos, R. N. Bisset, F. Ferlaino Can angular oscillations probe superfluidity in dipolar supersolids?, Phys. Rev. Lett. 129 40403 (2022-07-22), http://dx.doi.org/10.1103/PhysRevLett.129.040403 doi:10.1103/PhysRevLett.129.040403 (ID: 720697) Toggle Abstract
  Angular oscillations can provide a useful probe of the superfluid properties of a system. Such<br /> measurements have recently been applied to dipolar supersolids, which exhibit both density modulation and phase coherence, and for which robust probes of superfluidity are particularly interesting.<br /> So far, these investigations have been confined to linear droplet arrays. Here, we explore angular<br /> oscillations in systems with 2D structure, which in principle have greater sensitivity to superfluidity.<br /> Surprisingly, in both experiment and simulation, we find that the frequency of angular oscillations<br /> remains nearly unchanged even when the superfluidity of the system is altered dramatically. This<br /> indicates that angular oscillation measurements do not always provide a robust experimental probe<br /> of superfluidity with typical experimental protocols.
• T. Bland, E. Poli, C. Politi, L. Klaus, M. Norcia, F. Ferlaino, L. Santos, R. N. Bisset Two-Dimensional Supersolid Formation in Dipolar Condensates, Phys. Rev. Lett. 128 195302 (2022-05-13), http://dx.doi.org/10.1103/PhysRevLett.128.195302 doi:10.1103/PhysRevLett.128.195302 (ID: 720678)

2021

Articles

• E. Poli, T. Bland, C. Politi, L. Klaus, M. Norcia, F. Ferlaino, R. N. Bisset, L. Santos Maintaining supersolidity in one and two dimensions, Phys. Rev. A 104 63307 (2021-12-09), http://dx.doi.org/10.1103/PhysRevA.104.063307 doi:10.1103/PhysRevA.104.063307 (ID: 720729) Toggle Abstract
  We theoretically investigate supersolidity in three-dimensional dipolar Bose-Einstein condensates. We focus on the role of trap geometry in determining the dimensionality of the resulting droplet arrays, which range from one-dimensional to zigzag, through to two-dimensional supersolids in circular traps. Supersolidity is well established in one-dimensional arrays, and may be just as favorable in two-dimensional arrays provided that one appropriately scales the atom number to the trap volume. We develop a tractable variational model—which we benchmark against full numerical simulations—and use it to study droplet crystals and their excitations. We also outline how exotic ring and stripe states may be created with experimentally feasible parameters. Our work paves the way for future studies of two-dimensional dipolar supersolids in realistic settings.
• M. Norcia, C. Politi, L. Klaus, E. Poli, M. Sohmen, M. J. Mark, R. N. Bisset, L. Santos, F. Ferlaino Two-dimensional supersolidity in a dipolar quantum gas, Nature 596 361 (2021-08-18), http://dx.doi.org/10.1038/s41586-021-03725-7 doi:10.1038/s41586-021-03725-7 (ID: 720624)
• M. Sohmen, C. Politi, L. Klaus, L. Chomaz, M. J. Mark, M. Norcia, F. Ferlaino Birth, life, and death of a dipolar supersolid, Phys. Rev. Lett. 126 233401 (2021-06-07), http://dx.doi.org/10.1103/PhysRevLett.126.233401 doi:10.1103/PhysRevLett.126.233401 (ID: 720625) Toggle Abstract
  In the short time since the first observation of supersolid states of ultracold dipolar atoms, substantial progress has been made in understanding the zero-temperature phase diagram and low-energy excitations of these systems. Less is known, however, about their finite-temperature properties, particularly relevant for supersolids formed by cooling through direct evaporation. Here, we explore this realm by characterizing the evaporative formation and subsequent decay of a dipolar supersolid by combining high-resolution in-trap imaging with time-of-flight observables. As our atomic system cools toward quantum degeneracy, it first undergoes a transition from thermal gas to a crystalline state with the appearance of periodic density modulation. This is followed by a transition to a supersolid state with the emergence of long-range phase coherence. Further, we explore the role of temperature in the development of the modulated state.