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Jasper Smits

Publications and source records attributed to Jasper Smits.

3 recordsLinked to original sources

Imaging Spinor Bose Gasses Using Off-Axis Holography

We introduce a novel, non-invasive imaging technique based on spin-dependent off-axis holography (SOAH) for spin-1 Bose-Einstein condensates (BECs). Utilizing a dual reference beam strategy, this method records two orthogonal circular polarization components of a single probe beam. The circular birefringence of spin-polarized atoms induces differing complex phase shifts in the polarization components of the light, which are reconstructed from the interference patterns captured on camera. Our approach enables spin- and density-resolved imaging of both phase and amplitude information \emph{in-situ} on a sub-millisecond time scale with minimal disturbance to the condensate. We explore the technique's efficacy under various background static fields, demonstrating its sensitivity to the quantization axis of the atoms and confirming its effectiveness.

cond-mat.quant-gas

Dynamics of a Space-Time Crystal in an Atomic Bose-Einstein Condensate

A space-time crystal has recently been observed in a superfluid Bose gas. Here we construct a variational model that allows us to describe from first principles the coupling between the radial breathing mode and the higher-order axial modes that underlies the observation of the space-time crystal. By comparing with numerical simulations we verify the validity of our variational Ansatz. From the model we determine the requirements for the observation of the space-time crystal and the Ising-like nature of the symmetry breaking involved. Also, we find the onset and growth rate of the space-time crystal, which can be compared to experiments.

cond-mat.quant-gas

Observation of a space-time crystal in a superfluid quantum gas

Time crystals are a phase of matter, for which the discrete time symmetry of the driving Hamiltonian is spontaneously broken. The breaking of discrete time symmetry has been observed in several experiments in driven spin systems. Here, we show the observation of a space-time crystal using ultra-cold atoms, where the periodic structure in both space and time are directly visible in the experimental images. The underlying physics in our superfluid can be described ab initio and allows for a clear identification of the mechanism that causes the spontaneous symmetry breaking. Our results pave the way for the usage of space-time crystals for the discovery of novel nonequilibrium phases of matter.

cond-mat.quant-gas