Degenerate quantum gases with spin-orbit coupling: a review

Area of Science:

• Atomic, Molecular, and Optical Physics
• Condensed Matter Physics
• Quantum Simulation

Background:

• Synthetic spin-orbit (SO) coupling is crucial for creating novel quantum states in ultracold atomic gases.
• Understanding SO coupling is key to exploring phenomena like superfluidity and topological states.

Purpose of the Study:

• To review recent advancements in synthetic spin-orbit coupling in ultracold atomic gases.
• To discuss Raman and Rashba types of SO coupling and their implications.
• To highlight the impact of SO coupling on single-particle, two-body, and many-body physics.

Main Methods:

• Focus on theoretical aspects and experimental realizations of synthetic SO coupling.
• Analysis of single-particle properties, including ground state degeneracy and spin-momentum locking.
• Examination of two-body interactions and their influence on fermion pairing and superfluidity.

Main Results:

• SO coupling leads to novel superfluidity features and richer phase diagrams.
• Increased low-energy density-of-state enhances interaction effects.
• Absence of Galilean invariance and spin-momentum locking result in intriguing quantum dynamics and critical velocities.
• Mixing of singlet and triplet states creates novel fermion pairing and topological superfluids.

Conclusions:

• Investigating SO coupling in cold atoms enriches understanding of fundamental phenomena like superfluidity.
• Cold atom systems with SO coupling serve as platforms for simulating condensed matter states, including topological superfluids.
• This research paves the way for novel quantum systems like SO-coupled unitary Fermi gases and high-spin quantum gases.