25,023 research outputs found
Thermal Logic Gates: Computation with phonons
Logic gates are basic digital elements for computers. We build up thermal
logic gates that can perform similar operations as their electronic
counterparts. The thermal logic gates are based on the nonlinear lattices,
which exhibit very intriguing phenomena due to their temperature dependent
power spectra. We demonstrate that phonons, the heat carriers, can be also used
to carry information and processed accordingly. The possibility of nanoscale
experiment is discussed.Comment: 5 pages, 5 figures. To appear in Phys. Rev. Let
Quantum Computer with Mixed States and Four-Valued Logic
In this paper we discuss a model of quantum computer in which a state is an
operator of density matrix and gates are general quantum operations, not
necessarily unitary. A mixed state (operator of density matrix) of n two-level
quantum systems is considered as an element of 4^n-dimensional operator Hilbert
space (Liouville space). It allows to use a quantum computer model with
four-valued logic. The gates of this model are general superoperators which act
on n-ququat state. Ququat is a quantum state in a four-dimensional (operator)
Hilbert space. Unitary two-valued logic gates and quantum operations for an
n-qubit open system are considered as four-valued logic gates acting on
n-ququat. We discuss properties of quantum four-valued logic gates. In the
paper we study universality for quantum four-valued logic gates.Comment: 17 page
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