arXiv subjects

Mihail Teodorescu-Frumosu

Publications and source records attributed to Mihail Teodorescu-Frumosu.

2 recordsLinked to original sources

arXiv2003

Invariants of multiple-qubit systems under stochastic local operations

We investigate the behavior of quantum states under stochastic local quantum operations and classical communication (SLOCC) for fixed numbers of qubits. We explicitly exhibit the homomorphism between complex and real groups for two-qubits, and use the latter to describe the effect of SLOCC operations on two-qubit states. We find an expression for the polarization Lorentz group invariant length, which is the Minkowskian analog of the quantum state purity, the corresponding Euclidean length. The construction presented is immediately generalizable to any finite number of qubits.

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arXiv2003

A multi-photon Stokes-parameter invariant for entangled states

We consider the Minkowskian norm of the n-photon Stokes tensor, a scalar invariant under the group realized by the transformations of stochastic local quantum operations and classical communications (SLOCC). This invariant is offered as a candidate entanglement measure for n-qubit states and discussed in relation to measures of quantum state entanglement for certain important classes of two-qubit and three-qubit systems. This invariant can be directly estimated via a quantum network, obviating the need to perform laborious quantum state tomography. We also show that this invariant directly captures the extent of entanglement purification due to SLOCC filters.

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