Supersolids: unveiling an extraordinary quantum phase of matter

Introduction

Supersolids are a paradoxical quantum phase of matter that combines the properties of superfluids and crystals, searched for a long time in quantum solids and many other systems. Recently, we discovered a novel cluster phase in a quantum gas of magnetic atoms which realizes a supersolid. However, the limited size, the inhomogeneity, and the lack of appropriate detection methods have allowed so far to assess only very basic properties of supersolids.

Proposed Methodology

Here I propose an innovative density-phase microscope and original ideas that combine the best of matter-wave and condensed-matter methods to unveil the extraordinary properties of supersolids.

Measurement Techniques

With a two-layer superfluid-supersolid configuration, we will measure both density and phase of the supersolid. The following techniques will be employed:

1. Controllable Optical Potentials: We will realize large, homogeneous crystal geometries in 1D and 2D.
2. High-Resolution Optical Addressing: This will allow us to manipulate locally the wavefunction, e.g., creating phase patterns or force fields, and we will follow the local dynamics.

Research Goals

Our main goal is to explore fundamental properties that are largely unknown even theoretically:

• Variable superfluid density under rotation
• Variable angular momentum of quantized vortices
• Dissipation-less deformation of the crystal
• Josephson effect without barriers
• Quantum entanglement properties

Exploration of New Supersolid Types

We will also attempt the realization of new types of supersolid to prove the generality of the phenomena:

• With coupled supersolid layers, we will move towards supersolidity in 3D.
• Using a quasi-2D environment, we will attempt to realize two proposed types of strongly interacting and strongly correlated supersolids.

Connections to Other Quantum Phases

Our work will establish connections between supersolids and other patterned quantum phases, such as:

• Pair-density waves in superconductors and in helium superfluids
• Intertwined phases in low-dimensional superfluids
• Pasta phases in neutron stars

Our work might open directions for the realization of materials with novel functionalities.