PubMed Health⌕ Search

Biomedical subjects

M Inguscio

Publications and source records attributed to M Inguscio.

33 records · Page 2Linked to original sources
PubMed2001

Bose-Einstein condensation of potassium atoms by sympathetic cooling.

We report on the Bose-Einstein condensation of potassium atoms, whereby quantum degeneracy is achieved by sympathetic cooling with evaporatively cooled rubidium. Because of the rapid thermalization of the two different atoms, the efficiency of the cooling process is high. The ability to achieve condensation by sympathetic cooling with a different species may provide a route to the production of degenerate systems with a larger choice of components.

Journal Article↗
PubMed2001

Time-domain atom interferometry across the threshold for Bose-Einstein condensation.

We have performed time-domain interferometry experiments with matter waves trapped in a harmonic potential above and below the Bose-Einstein phase transition, by means of the method of separated oscillating fields, with a variable time delay T. We observe the oscillations of the population between two internal Zeeman states versus the delay T to be rapidly depleted both below and slightly above Bose-Einstein condensation. We give a quantitative explanation in terms of the phase evolution due to the entanglement between the internal and external degrees of freedom.

Journal Article↗
PubMed2001

Josephson junction arrays with Bose-Einstein condensates.

We report on the direct observation of an oscillating atomic current in a one-dimensional array of Josephson junctions realized with an atomic Bose-Einstein condensate. The array is created by a laser standing wave, with the condensates trapped in the valleys of the periodic potential and weakly coupled by the interwell barriers. The coherence of multiple tunneling between adjacent wells is continuously probed by atomic interference. The square of the small-amplitude oscillation frequency is proportional to the microscopic tunneling rate of each condensate through the barriers and provides a direct measurement of the Josephson critical current as a function of the intermediate barrier heights. Our superfluid array may allow investigation of phenomena so far inaccessible to superconducting Josephson junctions and lays a bridge between the condensate dynamics and the physics of discrete nonlinear media.

Journal Article↗
PubMed2001

Superfluid and dissipative dynamics of a Bose-Einstein condensate in a periodic optical potential.

We create Bose-Einstein condensates of 87Rb in a static magnetic trap with a superimposed blue-detuned 1D optical lattice. By displacing the magnetic trap center we are able to control the condensate evolution. We observe a change in the frequency of the center-of-mass oscillation in the harmonic trapping potential, in analogy with an increase in effective mass. For fluid velocities greater than a local speed of sound, we observe the onset of dissipative processes up to full removal of the superfluid component. A parallel simulation study visualizes the dynamics of the Bose-Einstein condensate and accounts for the main features of the observed behavior.

Journal Article↗
PubMed2001

Search for exchange-antisymmetric states for spin-0 particles at the 10(-11) level.

We set a new upper limit of 1.7x10(-11) to the probability that two spin-0 16O nuclei are in forbidden exchange-antisymmetric states, testing the validity of fundamental principles of quantum mechanics. A newly designed difference-frequency spectrometer is used to look for the existence of these states. The experimental test was performed by tuning the spectrometer across a molecular transition of 12C 16O (2) belonging to the rovibrational band at 4.25 microm, connecting the forbidden states (00(0)0,J = 25) and (00(0)1,J = 26).

Journal Article↗
PubMed2000

Collective oscillations of two colliding bose-einstein condensates

Two 87Rb condensates ( F = 2, m(f) = 2, and m(f) = 1) are produced in highly displaced harmonic traps and the collective dynamical behavior is investigated. The mutual interaction between the two condensates is evidenced in the center-of-mass oscillations as a frequency shift of 6.4(3)%. Calculations based on a mean-field theory well describe the observed effects of periodical collisions both on the center-of-mass motion and on the shape oscillations.

Journal Article↗