Controlling entanglement in the interferometry of driven coupled flux qubits

We propose a fluxon-controlled quantum computer incorporated with three-qubit quantum error correction using special gate operations, i.e. joint-phase and SWAP gate operations, inherent in capacitively coupled superconducting flux qubits. The proposed quantum computer acts exactly like a knitting machine at home.

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Realizing various approximate quantum cloning with XY-type exchange interactions of flux qubits

International Journal of Modern Physics B ◽

10.1142/s0217979214500817 ◽

2014 ◽

Vol 28 (14) ◽

pp. 1450081 ◽

Cited By ~ 1

Author(s):

Na Li ◽

Liu Ye

Keyword(s):

Quantum Interference ◽

Exchange Interactions ◽

Quantum Cloning ◽

Superconducting Quantum Interference Devices ◽

Superconducting Quantum Interference ◽

Flux Qubits ◽

Universal Quantum ◽

Experimental Technology ◽

Real State

In this paper, we realize all kinds of 1 → 2 approximate quantum cloning, including optimal 1 → 2 symmetric (or asymmetric) universal quantum cloning (UQC) and phase-covariant cloning (PCC), symmetric economical phase-covariant cloning (EPCC) and real state quantum cloning, with the XY-type exchange interactions of the flux qubits which are coupled by dc superconducting quantum interference devices (SQUIDs). It is shown that our schemes can be realized with the current experimental technology.

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Galvanic Phase Coupling of Superconducting Flux Qubits

Applied Sciences ◽

10.3390/app112311309 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11309

Author(s):

Mun Dae Kim

Keyword(s):

Coupling Strength ◽

Fault Tolerant ◽

Coupled System ◽

Inductive Coupling ◽

Galvanic Coupling ◽

Flux Qubits ◽

Superconducting Flux Qubits ◽

Qubit Gate ◽

Central Loop ◽

Fundamental Boundary

We investigate the galvanic coupling schemes of superconducting flux qubits. From the fundamental boundary conditions, we obtain the effective potential of the coupled system of two or three flux qubits to provide the exact Lagrangian of the system. While usually the two-qubit gate has been investigated approximately, in this study we derive the exact inductive coupling strength between two flux qubits coupled directly and coupled through a connecting central loop. We observe that the inductive coupling strength needs to be included exactly to satisfy the criteria of fault-tolerant quantum computing.

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