Degenerate Quantum Gases and Atom Optics

Degenerate quantum gases arise when ultracold atomic vapours occupy quantum states whose thermal de Broglie wavelength exceeds the mean interparticle spacing. In Bose–Einstein condensates (BECs) bosons collapse into a single matter-wave mode, displaying macroscopic coherence, superfluidity and quantised vortices. Degenerate Fermi gases, by contrast, form a Fermi sea with Pauli exclusion driving pairing correlations that span the BCS–BEC crossover. Atom optics exploits coherent matter waves in analogue to laser light, realising beam splitters, interferometers and matter-wave guides on atom chips or in optical lattices. Tunable interactions via Feshbach resonances, hybrid coupling to light fields and engineered potentials permit quantum simulation of condensed-matter models, tests of many-body dynamics and precision metrology. This interplay of quantum statistics, interactions and atom-optical control has led to novel phenomena such as quantum droplets, supersolidity and artificial gauge fields, with applications in gravimetry, inertial sensing and quantum information.

Research from Nature Portfolio

Rotating quantum fluids have revealed analogues of curved spacetime dynamics. A record-breaking experiment stabilised a giant multiquantum vortex in superfluid helium, whose compact core carries thousands of circulation quanta. By tracking interfacial wave–vortex interactions, researchers observed bound states and ring-down signatures akin to rotating black-hole spacetimes, opening a new platform for finite-temperature quantum field simulations. In parallel, studies of rotating quantum wave turbulence in Bose condensates demonstrated energy transfer from large-scale inertial waves into Kelvin-wave cascades on quantised vortices. By modulating angular velocity, investigators exposed a boundary-driven energy injection mechanism distinct from classical Ekman layers and directly observed the transition to a pure wave-turbulence regime at ultralow temperatures.

Degenerate Quantum Gases and Atom Optics publication trend

The graph below shows the total number of articles in degenerate quantum gases and atom optics across all publications each year (not limited to Nature Index journals).

Technical terms

Bose–Einstein condensate: A macroscopic quantum state formed when bosonic atoms occupy a single ground matter-wave mode at ultralow temperatures.

Degenerate Fermi gas: A quantum gas of fermions cooled below the Fermi temperature, filling all momentum states up to the Fermi energy under the Pauli exclusion principle.

Atom interferometry: A precision measurement technique in which coherent matter waves are split and recombined to probe phase shifts from external fields or inertial effects.

Feshbach resonance: A mechanism for tuning interatomic interactions by aligning a bound molecular state with the scattering continuum using a magnetic field.

Tan’s two-body contact: A universal parameter quantifying short-range correlations in an interacting quantum gas, governing high-momentum and high-frequency tails.

Quantised vortex: A topological defect in a superfluid or condensate where circulation around the core is restricted to integer multiples of Planck’s constant divided by mass.

References

1. Rotating quantum wave turbulence. Nature Physics (2023).
2. Rotating curved spacetime signatures from a giant quantum vortex. Nature (2024).
3. Testing universality of Feynman-Tan relation in interacting Bose gases using high-order Bragg spectra. Light: Science & Applications (2023).
4. Evolution from Bardeen–Cooper–Schrieffer to Bose–Einstein Condensation in Two Dimensions: Crossovers and Topological Quantum Phase Transitions. Annual Review of Condensed Matter Physics (2024).