Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 23: Quantum Information: Concepts and Methods IV

Q 23.4: Talk

Tuesday, March 1, 2016, 15:15–15:30, e214

Characterising ground and thermal states of few-body Hamiltonians — •Felix Huber and Otfried Gühne — Universität Siegen

Hamiltonians of naturally occuring physical systems are expected to have few-body interactions only. Accordingly, these Hamiltonians impose only local constraints onto the quantum states governed by them. Thus motivated, we characterise the set of ground and thermal states of few-body Hamiltonians, leading to new insights into the quantum marginal problem and to a generalisation of entanglement. We provide both witnesses as well as a semi-definite program to detect states outside of the convex hull of thermal and ground states having few-body Hamiltonians only. Finally, we give numerical results on the fraction of pure states determined by their marginals, and explore connections to the detection of topologically ordered states.