Macroscopic Quantum Phenomena

Macroscopic Quantum Phenomena

Quantum physics is generally characterized as the science of the very small, but under certain circumstances quantum effects lead to dramatic changes in the properties of materials on macroscopic scales. ‘Macroscopic’ quantum phenomena involve collective behavior of enormous numbers of interacting quantum particles, and quantitative analysis of many of these systems (like high temperature superconductors) is extremely challenging. Many-body quantum systems are often difficult to handle theoretically, and in some important cases the true nature of the phase diagram is not yet accurately known. One possible path to gain deeper understanding of these incredibly rich physical systems is to engineer a “synthetic” many body quantum system that maps onto a particular system of interest, but has more conveniently tunable properties.

One important advantage to studying quantum states of matter using ultracold atoms is that we can control the interactions between the atoms by varying an externally applied magnetic field.The ability to make the interactions weak or strong, attractive or repulsive, allows us to extract far more information about a given system than when these parameters are not tunable, as is the case with most  “real” condensed matter systems.

Recent Posts

Manuscript on Thermal Phase Fluctuations Submitted to PRA

Parth Sabharwal has completed an extensive study of thermal phase fluctuations appearing in narrow superfluid rings, testing some interesting predictions made by a colleague Ludwig Mathey over a decade ago, and we have submitted a manuscript describing his work to Physical Review A.

Thermal Phase Fluctuations in Narrow Superfluid Rings (arXiv)

Using matter-wave interference, we have investigated thermal phase fluctuations in narrow coplanar, concentric rings of ultracold fermionic superfluids. We found that the correlation length decreases with number density, consistent with theoretical expectations. We also observed that increasing the coupling between the rings leads to greater overall coherence in the system. The phase fluctuations increased with a change from periodic to closed boundary conditions as we applied a potential barrier at one point in a ring. These results are relevant for the implementation of proposals to utilize ultracold quantum gases in large and elongated circuit-like geometries, especially those that require deterministic preparation and control of quantized circulation states.

  1. Paper on Quench-Induced Spontaneous Currents Published in PRA Comments Off on Paper on Quench-Induced Spontaneous Currents Published in PRA
  2. Congratulations to Dr. Allman Comments Off on Congratulations to Dr. Allman
  3. Mitigating Fermion Hole Heating Comments Off on Mitigating Fermion Hole Heating
  4. Published in Physical Review Letters Comments Off on Published in Physical Review Letters