IMPLEMENTING AN n-QUBIT FREDKIN GATE WITH SUPERCONDUCTING QUANTUM-INTERFERENCE DEVICES IN CAVITY QED

2011 ◽  
Vol 25 (21) ◽  
pp. 2915-2924 ◽  
Author(s):  
ANSHOU ZHENG ◽  
YONGJIN CHENG ◽  
JIBIN LIU ◽  
XICHENG WANG ◽  
YUAN ZHENG
Keyword(s):  
Quantum Interference ◽  
Cavity Qed ◽  
Vacuum State ◽  
Superconducting Quantum Interference Device ◽  
Alternative Scheme ◽  
Superconducting Quantum Interference Devices ◽  
Superconducting Quantum Interference ◽  
Fredkin Gate ◽  
Logical Gate

An alternative scheme is proposed in this paper to realize an n-qubit Fredkin gate with superconducting quantum-interference device (SQUID) in cavity QED. The multiqubit logical gate is essentially accomplished by a sequence of operations on only two SQUIDs in a large-detuned cavity. In the scheme, the two logical states of a qubit are presented by the two lowest states of a SQUID and the cavity is always in vacuum state so that the limit on the cavity is not serious.

CORRELATION OF SUPERCURRENTS IN TWO DISTANT MESOSCOPIC SQUID RINGS IN THE PRESENCE OF TWO-MODE NONCLASSICAL FIELD

2005 ◽  
Vol 19 (11) ◽  
pp. 1965-1971 ◽  
Author(s):  
Z. H. PENG ◽  
J. ZOU ◽  
B. SHAO ◽  
J. F. CAI
Keyword(s):  
Quantum Interference ◽  
Vacuum State ◽  
Superconducting Quantum Interference Device ◽  
Squeezed Vacuum State ◽  
Squeezed Vacuum ◽  
Superconducting Quantum Interference ◽  
Squid Rings ◽  
Degree Of Entanglement

In this paper we consider two distant mesoscopic superconducting quantum interference device (SQUID) rings A and B in the presence of two-mode squeezed vacuum state field, and aim to see the effect of the field on the correlation of supercurrents in the two rings. We know the degree of entanglement of the two-mode squeezed vacuum state increases with the squeezing parameter r. In this paper we find that the correlation of the supercurrents increases with the parameter r too, meaning that the correlation of the supercurrents increases with the degree of entanglement of the field.

SCHEME FOR IMPLEMENTING AN N-QUBIT CONTROLLED NOT GATE WITH SUPERCONDUCTING QUANTUM INTERFERENCE DEVICES IN CAVITY QED

2010 ◽  
Vol 08 (08) ◽  
pp. 1337-1345
Author(s):  
BAO-LONG FANG ◽  
ZHEN YANG ◽  
LIU YE
Keyword(s):  
Quantum Interference ◽  
Cavity Qed ◽  
Resonant Cavity ◽  
Coupling Constants ◽  
Toffoli Gate ◽  
Superconducting Quantum Interference Devices ◽  
Superconducting Quantum Interference ◽  
Cavity Coupling ◽  
Coupling Error

We present a scheme for implementing a Toffoli gate. The superconducting quantum interference devices are coupled to a resonant cavity with nonidentical SQUID–cavity coupling constants. So only one interaction between SQUID and cavity is required, and a Toffoli gate can be obtained. The method can be generalized to the N-qubit case easily and the scheme is insensitive to systematic coupling error.

REALIZATION OF THE GREENBERG–HORNE–ZEILINGER (GHZ) STATE AND SWAP GATE WITH SUPERCONDUCTING QUANTUM-INTERFERENCE DEVICES IN A CAVITY VIA ADIABATIC PASSAGE

2008 ◽  
Vol 22 (15) ◽  
pp. 1507-1513 ◽  
Author(s):  
AN-SHOU ZHENG ◽  
YONG-JIN CHENG ◽  
JI-BING LIU ◽  
TIE-PING LI
Keyword(s):  
Quantum Interference ◽  
Ghz State ◽  
Adiabatic Passage ◽  
Adiabatic Evolution ◽  
Alternative Scheme ◽  
Present Scheme ◽  
Superconducting Quantum Interference Devices ◽  
Superconducting Quantum Interference ◽  
Swap Gate ◽  
Cavity Damping

We propose an alternative scheme to prepare the Greenberg–Horne–Zeilinger (GHZ) state and realize a SWAP gate by using Superconducting Quantum-interference devices (SQUIDs) coupled to a cavity. The present scheme, based on the adiabatic evolution of dark state, constitutes a decoherence-free method in the sense that spontaneous emission and cavity damping are avoided. Besides, the standard GHZ state can be directly obtained without measurement or any auxiliary SQUIDs and the construction of the SWAP gate does not require a composition of elementary gates from a universal set. Thus the procedure is simplified and decoherence is greatly suppressed.

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