Tomasz Sowiński

Publications (3)7.37 Total impact

• Article: Few interacting fermions in one-dimensional harmonic trap

  Tomasz Sowiński, Tobias Grass, Omjyoti Dutta, Maciej Lewenstein
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  ABSTRACT: We study spin-1/2 fermions, interacting via a two-body contact potential, in a one-dimensional harmonic trap. Applying exact diagonalization, we investigate the behavior at finite interaction strength, and discuss the role of a ground state degeneracy which occurs for sufficiently strong repulsive interaction. Even low temperature or a completely depolarizing channel may then dramatically influence the system's behavior. We calculate level occupation numbers as signatures of thermalization, and we discuss the mechanisms to break the degeneracy.
  04/2013;
• Article: Violation of the universality hypothesis in ultra-cold atomic systems

  Tomasz Sowiński, Ravindra W. Chhajlany, Omjyoti Dutta, Luca Tagliacozzo, Maciej Lewenstein
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  ABSTRACT: We study the attractive Bose-Hubbard model with a tunable, on-site three-body constraint. It is shown that the critical behavior of the system undergoing a phase transition from pair-superfluid to superfluid at integer filling depends on the value of the three-body repulsion. In particular, a critical exponent and the central charge governing the quantum phase transitions are shown to have repulsion dependent features. In consequence, the model extends the list of known systems violating the universality hypothesis.
  04/2013;
• Source

  Available from: Philipp Hauke

  Article: Dipolar molecules in optical lattices.

  Tomasz Sowiński, Omjyoti Dutta, Philipp Hauke, Luca Tagliacozzo, Maciej Lewenstein
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  ABSTRACT: We study the extended Bose-Hubbard model describing an ultracold gas of dipolar molecules in an optical lattice, taking into account all on-site and nearest-neighbor interactions, including occupation-dependent tunneling and pair tunneling terms. Using exact diagonalization and the multiscale entanglement renormalization ansatz, we show that these terms can destroy insulating phases and lead to novel quantum phases. These considerable changes of the phase diagram have to be taken into account in upcoming experiments with dipolar molecules.
  Physical Review Letters 03/2012; 108(11):115301. · 7.37 Impact Factor