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We study a one-dimensional chain of nuclear 1/2 spins in an external time-dependent magnetic field, considered as a possible candidate for experimental realization of quantum computation. According to the general theory of interacting particles, one of the most dangerous effects is quantum chaos that can destroy the stability of quantum operations. The(More)
We propose a solid-state nuclear-spin quantum computer based on application of scanning tunneling microscopy (STM) and well-developed silicon technology. It requires the measurement of tunneling-current modulation caused by the Larmor precession of a single electron spin. Our envisioned STM quantum computer would operate at the high magnetic field(More)
We propose a nuclear spin quantum computer based on magnetic resonance force mi-croscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essetial requirements for quantum computation in solids: (a) preparation of the ground state, (b) one-and two-qubit quantum logic gates, and (c) a measurement of the final state. The(More)
The perturbation theory is developed based on small parameters which naturally appear in solid state quantum computation. We report the simulations of the dynamics of quantum logic operations with a large number of qubits (up to 1000). A nuclear spin chain is considered in which selective excitations of spins are provided by having a uniform gradient of the(More)
We study the properties of spectra and eigenfunctions for a chain of 1/2 spins (qubits) in an external time-dependent magnetic field and under the conditions of nonselective excitation (when the amplitude of the magnetic field is large). This model is known as a possible candidate for experimental realization of quantum computation. We present the theory(More)
We investigate the role of long-lasting quantum coherence in the efficiency of energy transport at room temperature in Fenna-Matthews-Olson photosynthetic complexes. The excitation energy transfer due to the coupling of the light harvesting complex to the reaction center (" sink ") is analyzed using an effective non-Hermitian Hamiltonian. We show that, as(More)
We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines well-developed silicon technology and expected advances in MRFM. Our proposal does not use electrostatic gates to realize quantum logic operations.
We study numerically the influence of non-resonant effects on the dynamics of a single π-pulse quantum CONTROL-NOT (CN) gate in a macroscopic ensemble of four-spin molecules at room temperature. The four nuclear spins in each molecule represent a four-qubit register. The qubits are " labeled " by the characteristic frequencies, ω k , (k = 0 to 3) due to the(More)
1 Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John’s, NL, Canada A1C 5S7 2 Theoretical Division, Los Alamos National Laboratory, MS B213, Los Alamos, NM 87545, USA 3 Dipartimento di Matematica e Fisica, and Interdisciplinary Laboratories for Advanced Materials Physics, Università Cattolica, Via Musei 41, 25121 Brescia,(More)