scholarly journals Study of Decoherence of Elementary Gates Implemented in a Chain of Few Nuclear Spins Quantum Computer Model

2012 ◽  
Vol 03 (01) ◽  
pp. 85-101 ◽  
Author(s):  
G. V. López ◽  
P. López
Keyword(s):  
Computer Model ◽  
Quantum Computer ◽  
Nuclear Spins ◽  
A Chain

scholarly journals Fidelity of noisy multiple-control reversible gates

2020 ◽  
Vol 23 (04) ◽  
pp. 385-392
Author(s):  
V.G. Deibuk ◽  
◽  
I.M. Yuriychuk ◽  
I. Lemberski ◽  
◽  
...  
Keyword(s):  
Frequency Control ◽  
Larmor Frequency ◽  
Interaction Constant ◽  
Frequency Noise ◽  
Nuclear Spins ◽  
Multiple Control ◽  
Correct Operation ◽  
Operation Algorithm ◽  
Semiconductor Matrix ◽  
A Chain

The effect of frequency noise on correct operation of the multiple-control Toffoli, Fredkin, and Peres gates has been discussed. In the framework of the Ising model, the energy spectrum of a chain of atoms with nuclear spins one-half in a spinless semiconductor matrix has been obtained, and allowed transitions corresponding to the operation algorithm of these gates have been determined. The fidelities of the obtained transitions were studied depending on the number of control qubits and parameters of the radio-frequency control pulses. It has been shown that correct operation of the Toffoli and Fredkin gates does not depend on the number of control qubits, while the Peres gate fidelity decreases significantly with the increasing number of control signals. The calculated ratios of the Larmor frequency to the exchange interaction constant correspond with the results of other studies.

scholarly journals Realization of a holonomic quantum computer in a chain of three-level systems

2015 ◽  
Vol 379 (47-48) ◽  
pp. 3050-3053 ◽  
Author(s):  
Zeynep Nilhan Gürkan ◽  
Erik Sjöqvist
Keyword(s):  
Quantum Computer ◽  
A Chain

IMPLEMENTATION OF QUANTUM LOGIC OPERATIONS AND CREATION OF ENTANGLEMENT BETWEEN TWO NUCLEAR SPIN QUBITS WITH CONSTANT INTERACTION

2006 ◽  
Vol 04 (06) ◽  
pp. 975-1001
Author(s):  
G. P. BERMAN ◽  
G. W. BROWN ◽  
M. E. HAWLEY ◽  
D. I. KAMENEV ◽  
V. I. TSIFRINOVICH
Keyword(s):  
Quantum Logic ◽  
Quantum Computer ◽  
Magnetic Field Gradient ◽  
Exchange Interactions ◽  
Conditional Logic ◽  
Perturbation Approach ◽  
Nuclear Spins ◽  
Logic Operations ◽  
Quantum Protocol ◽  
Silicon Based

We describe how to implement quantum logic operations in a silicon-based quantum computer with phosphorus atoms serving as qubits. The information is stored in the states of nuclear spins and the conditional logic operations are implemented through the electron spins using nuclear–electron hyperfine and electron–electron exchange interactions. The electrons in our computer should stay coherent only during implementation of one Controlled-NOT gate. The exchange interaction is constant, and selective excitations are provided by a magnetic field gradient. The quantum logic operations are implemented by rectangular radio-frequency pulses. This architecture is scalable and does not require manufacturing nanoscale electronic gates. As shown in this paper, parameters of a quantum protocol can be derived analytically even for a computer with a large number of qubits using our perturbation approach. We present the protocol for initialization of the nuclear spins and the protocol for creation of entanglement. All analytical results are tested numerically using a two-qubit system.

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