Related papers: A New Framework for Understanding Supersolidity in…
Although solid helium-4 (4He) may be a supersolid it also exhibits many phenomena unexpected in that context. We studied relaxation dynamics in the resonance frequency f(T) and dissipation D(T) of a torsional oscillator containing solid…
Our understanding of various states of matter usually relies on the assumption of thermodynamic equilibrium. However, the transitions between different phases of matter can be strongly affected by non-equilibrium phenomena. Here we…
Two-component Bose condensates with repulsive interaction are stable when $g_{\rm \scriptscriptstyle 1} g_{\rm \scriptscriptstyle 2}<g_{\rm \scriptscriptstyle 12}^{2}$ is satisfied. By tuning the interactions, we show that the instability…
For many years, $^4$He typified Bose-Einstein superfluids, but recent advances in dilute ultra-cold alkali-metal gases have provided new neutral superfluids that are particularly tractable because the system is dilute. This chapter starts…
Standard introductory modern physics textbooks do not exactly dwell on superfluidity in 4He. Typically, Bose-Einstein condensation (BEC) is mentioned in the context of an ideal Bose gas, followed by the statement that BEC happens in 4He and…
The ground state of solid $^4$He is studied using the diffusion Monte Carlo method and a new trial wave function able to describe the supersolid. The new wave function is symmetric under the exchange of particles and reproduces the…
The possibility of a supersolid state of matter, i.e., a crystalline solid exhibiting superfluid properties, first appeared in theoretical studies about forty years ago. After a long period of little interest due to the lack of experimental…
We calculate the mean-field phase diagram of a zero-temperature, binary Bose mixture on a square optical lattice, where one species possesses a non-negligible dipole moment. Remarkably, this system exhibits supersolidity for anomalously…
We have investigated the superfluid properties of a ring of weakly interacting and degenerate 1D Bose gas at thermal equilibrium with a rotating vessel. The conventional definition of superfluidity predicts that the gas has a significant…
The experimental realization of a thin layer of spin-polarized hydrogen adsorbed on top of the surface of superfluid 4He provides one of the best examples of a stable nearly two-dimensional quantum Bose gas. We report a theoretical study of…
We derive effective Hamiltonians for lattice bosons with strong geometrical frustration of the kinetic energy by projecting the interactions on the flat lowest Bloch band. Specifically, we consider the Bose Hubbard model on the one…
Superfluid 4He, the first superfluid ever discovered, is in some ways the least well understood. Unlike 3He superfluid, or the variety of Bose-Einstein condensates of ultracold gases, superfluid 4He is a very dense liquid of strongly…
Nearly a decade ago the old controversy about possible superfluid flow in the ground state of solid He4 was revived by the apparent experimental observation of such superflow. Although the experimentalists have recently retracted, very…
Supersolid is a long-sought exotic phase of matter, which is characterized by the coexistence of a diagonal long-range order of solid and an off-diagonal long-range order of superfluid. Possible candidates to realize such a phase have been…
It is pointed out that simulation computation of energy performed so far cannot be used to decide if the ground state of solid 4He has the number of lattice sites equal to the number of atoms (commensurate state) or if it is different…
We present a theory of hysteretic phenomena in Bose gases, using superfluidity in one dimensional rings and in optical lattices as primary examples. Through this study we are able to give a physical interpretation of swallowtail loops…
The concept of a supersolid state is paradoxical. It combines the crystallization of a many-body system with dissipationless flow of the atoms it is built of. This quantum phase requires the breaking of two continuous symmetries, the phase…
Can a gas behave like a crystal? Supersolidity is an intriguing and challenging state of matter which combines key features of superfluids and crystals. Predicted a long time ago, its experimental realization has been recently achieved in…
Integrating seminal ideas of London, Feynman, and Feenberg, this paper continues the development of an ab initio theory of the lambda transition in liquid 4He. The theory is based on variational determination of a trial density matrix…
We present neutron scattering results for the dynamic response by superfluid and normal-fluid 4He and the results of a simple perturbation-theory analysis which allows us to describe all aspects of the observed behavior by considering only…