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Quantum Information in the Frame of Coherent States

Domenii publicaţii > Fizica + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Du¹an Popov · Ioan Zaharie · Vjekoslav Sajfert · Ioan Luminosu · Deian Popov

Editorial: Springer, Int J Theor Phys, DOI 10.1007/s10773-007-9586-9, 2007.


Abstract In this paper we have showed that the qubit can be expressed through the coherent
states. Consequently, a message, i.e. a sequence of qubits, is expressed as a tensor
product of coherent states. In the quantum information theory and practice, only the code
and key message are expressed as a sequence of qubits, i.e. through a quantum channel, the
properly information will be transmitted by using a classical channel. Even if the most used
coherent states in the quantum information theory are the coherent states of the harmonic
oscillator (particularly, expressing by them the Schrödinger “cat states” and the Bell states),
several authors have been demonstrated that other kind of coherent states may be used in
quantum information theory. For the ensembles of qubits, we must use the density operator,
in order to describe the informational content of the ensemble. The diagonal representation
of the density operator, in the coherent state representation, is also useful to examine the
entanglement of the states.

Cuvinte cheie: Informatie cuantica, qubit, stari coerente, operatorul densitate // Quantum information, qubit, coherent state, density operator