Quantum turbulence lies at the heart of several nuclear physics applications. In particular, superfluidity likely holds the key to one of the outstanding mysteries in physics: pulsar glitches - sudden increases in the spinning of neutron stars even though they continually lose angular momentum. Quantum turbulence also appears in heavy ion collisions where the rapid excitation and subsequent quench of the system stimulates a cascade of energy.

This program aims to bring together experts on quantum turbulence from the fields of atomic physics, superfluid helium, nuclear physics, and astrophysics, to pave the road to a new understanding of quantum dynamics and its role in explaining pulsar glitches and heavy ion collisions.

The second week (March 25-29) of the program will be a workshop Quantum Turbulence: Experimental Insights led by Martin Zwierlein (MIT) and Wei Guo (U Florida) in which experimentalists from cold atom and liquid helium communities will share their insights, to be confronted with theory. A workshop registration fee of $50 will apply. The registration fee includes participation in the workshop, lectures, and coffee breaks.

With the exception of the workshop, we plan to follow the standard INT-program format of one or two daily talks with plenty of time for discussions and collaborations.

Themes

The program will be organized by themes intended to guide discussions between participants from different fields of physics. The exact nature of discussions each week will be flexible, depending on the interests of the participants.

Defining Quantum Turbulence (Week 1)

What exactly is quantum turbulence (QT)? How can it be identified and characterized in both formal and practical ways?

Quantitative Benchmarks for Theories of Quantum Turbulence (Weeks 1-2)

To understand quantum turbulence in remote applications (i.e. neutron stars), reliable theoretical techniques are required. These need to be validated quantitatively against reliable experimental and theoretical results. A goal might include identifying some benchmark problems accessible to both experiment and theory - convincing both communities to establish some results.

What can be Learned from Experiments? (Week 2)

What observables and techniques are available experimentally to study QT? Can application domains such as neutron stars and heavy ions be realized in cold atoms or Helium? Can relativistic theories be studied terrestrially?

From Microscopic to Macroscopic Turbulence (Weeks 3-4)

How can one make the transition from microscopic descriptions of processes like vortex reconnection that underlie QT but which tend to be computationally costly, and macroscopic hydrodynamic descriptions suitable for describing, i.e., neutron stars? What should successful macroscopic theories look like? (I.e. how many components are needed? For example, in superfluid 3 He- 4 He mixtures, a single normal sufficies, but for proton-neutron mixtures independent normal components are needed since the protons are charged.) How do the theories change when coarse-graining in space and/or time?

Classical vs. Quantum Turbulence (Weeks 4-5)

How do classical and quantum turbulence differ? What can we learn about classical turbulence from quantum turbulence and vice versa?