Anodic bonding was used to fabricate a 10 mm diameter × 640 nm tall annular geometry suitable for torsion pendulum studies of confined 3He. For pure 3He at saturated vapor pressure the inertia of the confined fluid was seen to be only partially coupled to the pendulum at 160 mK. Below 100 mK the liquid's inertial contribution was negligible, indicating a complete decoupling of the 3He from the pendulum. © 2009 Springer Science+Business Media, LLC.

This chapter is a progress report on the challenging yet promising frontier of quantum phase transitions (QPTs) in strongly correlated systems from the perspective of modern local probes and recent theoretical developments. The focus will be on our latest developments at this frontier. An outlook based on opportunities and questions emerging from these latest developments concludes the discussion. © Taylor & Francis Group.

Droplet pinch-off of fluids with liquid crystalline order is a common yet poorly understood process. We report on measurements of pinch-off dynamics for a lyotropic surfactant/water solution in the lamellar phase and a thermotropic liquid crystal in the smectic phase. We find pinch-off is universal and well described by a similarity solution for a strain thinning power-law fluid. This finding is consistent with bulk rheology measurements which show these materials shear thin with the appropriate power-law dependence.

We present the preliminary results of our studies of superfluid 3He in a 0.6 μm thick slab using NMR. Below T c the A phase is observed, and at low pressures the region of stability of the A phase extends down to the lowest temperatures reached, as described elsewhere. At pressures above 3.2 bar another, so far unidentified phase is observed at low temperatures. In this article we focus on the behavior of this phase and the transition between this phase and the A phase, all studied at 5.5 bar.

We present the first study of the phase diagram of a thick film of superfluid 3He confined within a nanofabricated slab geometry. This cryogenic microfluidic chamber provides a well-defined environment for the superfluid, in which both the regular geometry and surface roughness may be fully characterised. The chamber is designed with a slab thickness d=0.6 μm and 3 mm thick walls to allow pressure tuning of the effective confinement between 0 and 5.5 bar. Over this range the zero temperature superfluid coherence length, ξ 0, decreases by approximately a factor of two from 77 to 40 nm.

Measurements of the flow of thick 3He films over a highly polished silver surface, using a high precision torsional oscillator, have found unexpectedly long momentum relaxation times (Casey et al., Phys. Rev. Lett. 92, 255301, 2004). This results in a decoupling of the normal state helium film from the oscillator motion at low temperatures. In the ballistic regime the relaxation rate varies linearly with temperature.

We describe correlator product states, a class of numerically efficient many-body wave functions to describe strongly correlated wave functions in any dimension. Correlator product states introduce direct correlations between physical degrees of freedom in a simple way, yet provide the flexibility to describe a wide variety of systems. We show that many interesting wave functions can be mapped exactly onto correlator product states, including Laughlin's quantum Hall wave function, Kitaev's toric code states, and Huse and Elser's frustrated spin states.

We apply a low-frequency (mHz) ac pressure gradient to a sample of solid helium in order to search for a superfluidlike response. Our results are consistent with zero supersolid flow. Through a statistical analysis of our data, we set a bound on the rate of mass flow between two chambers, and hence the mass current density j. At the 68% confidence level, we bound v≡j/Ï≤9.6× 10-4 nm/s for the mass transport velocity. In terms of a simple model for the supersolid, we find an upper bound of 8.4× 10-6 for the supersolid fraction at 25 mK, at this same confidence level.

We study interaction-induced localization of electrons in an inhomogeneous quasi-one-dimensional system-a wire with two regions, one at low density and the other high. Quantum Monte Carlo techniques are used to treat the strong Coulomb interactions in the low-density region, where localization of electrons occurs. The nature of the transition from high to low density depends on the density gradient-if it is steep, a barrier develops between the two regions, causing Coulomb blockade effects. Ferromagnetic spin polarization does not appear for any parameters studied.

The intriguing idea that strongly interacting electrons can generate spatially inhomogeneous electronic liquid-crystalline phases is over a decade old 1-5 , but these systems still represent an unexplored frontier of condensed-matter physics. One reason is that visualization of the many-body quantum states generated by the strong interactions, and of the resulting electronic phases, has not been achieved. Soft condensed-matter physics was transformed by microscopies that enabled imaging of real-space structures and patterns.