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Entanglement of Formation of an Arbitrary State of Two Qubits
The entanglement of a pure state of a pair of quantum systems is defined as the entropy of either member of the pair. The entanglement of formation of a mixed state is defined as the minimum average
A single quantum cannot be cloned
If a photon of definite polarization encounters an excited atom, there is typically some nonvanishing probability that the atom will emit a second photon by stimulated emission. Such a photon is
Distributed Entanglement
Consider three qubits A, B, and C which may be entangled with each other. We show that there is a trade-off between A’s entanglement with B and its entanglement with C. This relation is expressed in
Entanglement of a Pair of Quantum Bits
The ``entanglement of formation'' of a mixed state \ensuremath{\rho} of a bipartite quantum system can be defined as the minimum number of singlets needed to create an ensemble of pure states that
Evolution without evolution: Dynamics described by stationary observables
Because the time parameter in the Schrodinger equation is not observable, energy apparently obeys a superselection rule in the same sense that charge does. That is, observables must all commute with
Statistical distance and Hilbert space
A concept of "statistical distance" is defined between different preparations of the same quantum system, or in other words, between different rays in the same Hilbert space. Statistical distance is
Teleporting an unknown quantum state via dual classical and EPR channels
An unknown quantum state ji can be disassembled into, then later reconstructed from, purely classical information and purely nonclassical EPR correlations. To do so the sender, \Alice," and the
Complementarity in the double-slit experiment: Quantum nonseparability and a quantitative statement of Bohr's principle
A detailed analysis of Einstein's version of the double-slit experiment, in which one tries to observe both wave and particle properties of light, is performed. Quantum nonseparability appears in the