Ehud Altman Group Page

a) b) c)

(a) When two perfect independent condensates interfere they produce a sharp interference pattern. What is the nature of the interference if the condensates are strongly fluctuating, as are, for example, one and two dimensional interacting Bose liquids? In this case the fringe intensity is essentially a quantum operator that fluctuates from shot to shot, leading to non trivial quantum noise (see references [1] and [2] under quantum noise below). (b) This noise is characterized by statistical distributions of the fringe amplitude, that depend on the nature of correlations in the quantum liquid. (c) In Ref [1] we point to some remarkable connections between the qunatum distribution of fringe contrast and the properties of a class of models relevant to fundamental physics. Thus a range of these models (conformal field theories with negative central charge c) can be investigated using interference experiments between Bose liquids with different values of the interaction.

Selected Publications:

Quantum Noise in ultra cold atomic systems

V. Gritsev, E. Altman, E. Demler, A. Polkovnikov, "Full quantum distribution of contrast in interference experiments between interacting one dimensional Bose liquids", cond-mat/0602475.
A. Polkovnikov, E. Altman, E. Demler, "Interference between independent fluctuating condensates", PNAS 103, 6125 (2006) .
E. Altman, E. Demler and M. D. Lukin, "Probing many body correlations of ultra-cold atoms via noise correlations", Phys. Rev. A. 70, 013603 (2004).

Non equilibrium Quantum dynamics in ultra cold atomic systems

E. Altman and A. Vishwanath, "Dynamic projection on Feshbach molecules: a probe of pairing and phase fluctuations", Phys. Rev. Lett. 95, 110404 (2005)
E. Altman, A. Polkovnikov, E. Demler, B. Halperin, M. D. Lukin, "Superfluid-insulator transition in a moving system of interacting bosons", Phys. Rev. Lett. 95, 020402 (2005).
E. Altman and A. Auerbach, "Oscillating Superfluidity of Bosons in Optical Lattices", Phys. Rev. Lett. {\bf 89}, 250404 (2002).

Strongly correlated electrons and quantum magnetism

D. Podolsky, E. Altman and T. Rostunov, E. Demler, "Competition between Triplet Superconductivity and Antiferromagnetism in Quasi One-Dimensional Electron Systems", Phys. Rev. B 70, 224503 (2004).
E. Altman, A. Polkovnikov, G. Refael and Y. Kafri, "Phase transition of one dimensional bosons with strong disorder", Phys. Rev. Lett. 93, 150402 (2004).
E. Berg, E. Altman and A. Auerbach, "Singlet Excitations in Pyrochlore: A Study of Quantum Frustration", Phys. Rev. Lett. 90, 147204 (2003).
E. Altman and A. Auerbach, "Plaquette Boson-Fermion Model of Cuprates", Phys. Rev. B {\bf 65}, 104508 (2002).
E. Altman and A. Auerbach, "Haldane gap and fractional oscillations in gated Josephson arrays", Phys Rev Lett {\bf 81} 4484-4487 (1998).

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a)	b)	c)
(a) When two perfect independent condensates interfere they produce a sharp interference pattern. What is the nature of the interference if the condensates are strongly fluctuating, as are, for example, one and two dimensional interacting Bose liquids? In this case the fringe intensity is essentially a quantum operator that fluctuates from shot to shot, leading to non trivial quantum noise (see references [1] and [2] under quantum noise below). (b) This noise is characterized by statistical distributions of the fringe amplitude, that depend on the nature of correlations in the quantum liquid. (c) In Ref [1] we point to some remarkable connections between the qunatum distribution of fringe contrast and the properties of a class of models relevant to fundamental physics. Thus a range of these models (conformal field theories with negative central charge c) can be investigated using interference experiments between Bose liquids with different values of the interaction.