Artykuły (WFAIS) Przeglądanie wg słów kluczowych "Quantum Physics"
Repozytorium Uniwersytetu Mikołaja Kopernika
Artykuły (WFAIS) Przeglądanie wg słów kluczowych "Quantum Physics"
Wyświetlono pozycje 1-20 z 51
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(2010)We analyze special class of bipartite states - so called Bell diagonal states. In particular we provide new examples of bound entangled Bell diagonal states and construct the class of entanglement witnesses diagonal in the ...
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(2010-04-08)We analyze a class of dynamics of open quantum systems which is governed by the dynamical map mutually commuting at different times. Such evolution may be effectively described via spectral analysis of the corresponding ...
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(2012-11-05)Exposed positive maps in matrix algebras define a dense subset of extremal maps. We provide a class of indecomposable positive maps in the algebra of 2n x 2n complex matrices with n>1. It is shown that these maps are exposed ...
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(2007-11-28)We construct a new class of positive indecomposable maps in the algebra of `d x d' complex matrices. These maps are characterized by the `weakest' positivity property and for this reason they are called atomic. This class ...
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(2011-01-30)We provide a multi-parameter family of 2-qudit PPT entangled states which generalizes the celebrated Horodecki state in 3 x 3. The entanglement of this family is identified via semidefinite programming based on "PPT symmetric ...
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(2006-04-03)We construct a new class of PPT states for bipartite "d x d" systems. This class is invariant under the maximal commutative subgroup of U(d) and contains as special cases almost all known examples of PPT states. Theses ...
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(2010-11-02)We provide a simple class of 2-qudit states for which one is able to formulate necessary and sufficient conditions for separability. As a byproduct we generalize well known construction provided by Horodecki et al. for ...
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(2011-04-10)We analyze a class of 2-qudit circulant states. They define generalization of well known 2-qubit X-states. We formula the necessary and sufficient criteria for vanishing quantum discord. We illustrate our analysis by an ...
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(2009-07-14)We provide a new class of indecomposable entanglement witnesses. In 4 x 4 case it reproduces the well know Breuer-Hall witness. We prove that these new witnesses are optimal and atomic, i.e. they are able to detect the ...
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(2010-06-15)We provide a class of optimal nondecomposable entanglement witnesses for 4N x 4N composite quantum systems or, equivalently, a new construction of nondecomposable positive maps in the algebra of 4N x 4N complex matrices. ...
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(2010-02-18)We show that each entanglement witness detecting given bipartite entangled state provides an estimation of its concurrence. We illustrate our result with several well known examples of entanglement witnesses and compare ...
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(2012-03-02)Exposed positive maps in matrix algebras define a dense subset of extremal maps. We provide a sufficient condition for a positive map to be exposed. This is an analog of a spanning property which guaranties that a positive ...
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(2010-10-22)We provided a class of legitimate memory kernels leading to completely positive trace preserving dynamical maps. Our construction is based on a simple normalization procedure. Interestingly, when applied to the celebrated ...
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(2008-08-26)In a series of papers with Kossakowski, the first author has examined properties of densities for which the positive partial transpositrionm (PPT) property can be readily checked. These densities were also investigated ...
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(2010-06-14)We propose a complete treatment of a local in time dynamics of open quantum systems. In this approach Markovian evolution turns out to be a special case of a general non-Markovian one. We provide a general representation ...
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(2011-05-24)We characterize a convex subset of entanglement witnesses for two qutrits. Equivalently, we provide a characterization of the set of positive maps in the matrix algebra of 3 x 3 complex matrices. It turns out that boundary ...
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(2009-02-05)We provide a new class of positive maps in matrix algebras. The construction is based on the family of balls living in the space of density matrices of n-level quantum system. This class generalizes the celebrated Choi map ...
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(2007-12-07)We present very simple method for constructing indecomposable entanglement witnesses out of a given pair -- an entanglement witness W and the corresponding state detected by W. This method may be used to produce new classes ...
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(2010-01-19)If the dynamics of an open quantum systems is non-Markovian, its {asymptotic} state strongly depends on the initial conditions, even if the dynamics possesses an {invariant} state. This is the very essence of memory effects. ...
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(2012-01-28)We characterize a class of Markovian dynamics using the concept of divisible dynamical map. Moreover we provide a family of criteria which can distinguish Markovian and non-Markovian dynamics. These Markovianity criteria ...
Wyświetlono pozycje 1-20 z 51