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Quantum Physics

Dartmouth Scholarship

2015

Quantum physics

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Effective Microscopic Models For Sympathetic Cooling Of Atomic Gases, Roberto Onofrio, Bala Sundaram Sep 2015

Effective Microscopic Models For Sympathetic Cooling Of Atomic Gases, Roberto Onofrio, Bala Sundaram

Dartmouth Scholarship

Thermalization of a system in the presence of a heat bath has been the subject of many theoretical investigations especially in the framework of solid-state physics. In this setting, the presence of a large bandwidth for the frequency distribution of the harmonic oscillators schematizing the heat bath is crucial, as emphasized in the Caldeira-Leggett model. By contrast, ultracold gases in atomic traps oscillate at well-defined frequencies and therefore seem to lie outside the Caldeira-Leggett paradigm. We introduce interaction Hamiltonians which allow us to adapt the model to an atomic physics framework. The intrinsic nonlinearity of these models differentiates them from …


Switching Quantum Dynamics For Fast Stabilization, Pierre Scaramuzza, Francesco Ticozzi Mar 2015

Switching Quantum Dynamics For Fast Stabilization, Pierre Scaramuzza, Francesco Ticozzi

Dartmouth Scholarship

Control strategies for dissipative preparation of target quantum states, both pure and mixed, and subspaces are obtained by switching between a set of available semigroup generators. We show that the class of problems of interest can be recast, from a control-theoretic perspective, into a switched-stabilization problem for linear dynamics. This is attained by a suitable affine transformation of the coherence-vector representation. In particular, we propose and compare stabilizing time-based and state-based switching rules for entangled state preparation, showing that the latter not only ensure faster convergence with respect to nonswitching methods, but can be designed so that they retain robustness …