Quantum Entanglement in Random Physical States

Detection of quantum entanglement in physical systems

Quantum entanglement is a fundamental concept both in quantum mechanics and in quantum information science. It encapsulates the shift in paradigm, for the description of the physical reality, brought by quantum physics. It has therefore been a key element in the debates surrounding the foundations of quantum theory. Entanglement is also a physical resource of great practical importance, instrum...

Monogamy and entanglement in tripartite quantum states

We present an interesting monogamy equation for (2⊗ 2⊗ n)-dimensional pure states, by which a quantity is found to characterize the tripartite entanglement with the GHZ type and W type entanglements as a whole. In particular, we, for the first time, reveals that for any quantum state of a pair of qubits, the difference between the two remarkable entanglement measures, concurrence and negativity...

Detecting entanglement of random states with an entanglement witness

The entanglement content of high-dimensional random pure states is almost maximal, nevertheless, we show that, due to the complexity of such states, the detection of their entanglement using witness operators is rather difficult. We discuss the case of unknown random states, and the case of known random states for which we can optimize the entanglement witness. Moreover, we show that coarse gra...

GEOMETRY OF QUANTUM STATES An Introduction to Quantum Entanglement GEOMETRY OF QUANTUM STATES An Introduction to Quantum Entanglement

Optimal entanglement criterion for mixed quantum states.

We develop a strong and computationally simple entanglement criterion. The criterion is based on an elementary positive map Phi which operates on state spaces with even dimension N > or = 4. It is shown that Phi detects many entangled states with a positive partial transposition (PPT) and that it leads to a class of optimal entanglement witnesses. This implies that there are no other witnesses ...