Rotons in Interacting Ultracold Bose Gases

Journal Article · Fri Sep 30 00:00:00 EDT 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.107.140401· OSTI ID:21611792

Cormack, Samuel C; Schumayer, Daniel; Hutchinson, David A. W. ^[1]

---

1. Jack Dodd Centre for Quantum Technology, Department of Physics, University of Otago, Dunedin (New Zealand)

In three dimensions, noninteracting bosons undergo Bose-Einstein condensation at a critical temperature, T{sub c}, which is slightly shifted by {Delta}T{sub c}, if the particles interact. We calculate the excitation spectrum of interacting Bose systems, {sup 4}He and {sup 87}Rb, and show that a roton minimum emerges in the spectrum above a threshold value of the gas parameter. We provide a general theoretical argument for why the roton minimum and the maximal upward critical temperature shift are related. We also suggest two experimental avenues to observe rotons in condensates. These results, based upon a path-integral Monte Carlo approach, provide a microscopic explanation of the shift in the critical temperature and also show that a roton minimum does emerge in the excitation spectrum of particles with a structureless, short-range, two-body interaction.

• OSTI ID: 21611792
• Journal Information: Physical Review Letters, Vol. 107, Issue 14; Other Information: DOI: 10.1103/PhysRevLett.107.140401; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
BOSONS
CRITICAL TEMPERATURE
EXCITATION
HELIUM 4
MONTE CARLO METHOD
PATH INTEGRALS
ROTONS
RUBIDIUM 87
SPECTRA
TWO-BODY PROBLEM
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCULATION METHODS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
HELIUM ISOTOPES
INTEGRALS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MANY-BODY PROBLEM
NUCLEI
ODD-EVEN NUCLEI
PHYSICAL PROPERTIES
QUASI PARTICLES
RADIOISOTOPES
RUBIDIUM ISOTOPES
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
YEARS LIVING RADIOISOTOPES