Incoherent and Coherent Tunneling of Macroscopic Phase in Flux Qubits

2004 ◽  
pp. 161-169 ◽  
Author(s):  
S. Saito ◽  
H. Tanaka ◽  
H. Nakano ◽  
M. Ueda ◽  
H. Takayanagi
Keyword(s):  
Flux Qubits ◽  
Coherent Tunneling

scholarly journals Superradiance with an ensemble of superconducting flux qubits

2016 ◽  
Vol 94 (22) ◽  
Author(s):  
Neill Lambert ◽  
Yuichiro Matsuzaki ◽  
Kosuke Kakuyanagi ◽  
Natsuko Ishida ◽  
Shiro Saito ◽  
...  
Keyword(s):  
Flux Qubits ◽  
Superconducting Flux Qubits

Fluxon-controlled quantum computer

2016 ◽  
Vol 14 (07) ◽  
pp. 1650040
Author(s):  
Toshiyuki Fujii ◽  
Shigemasa Matsuo ◽  
Noriyuki Hatakenaka
Keyword(s):  
Error Correction ◽  
Quantum Computer ◽  
Quantum Error Correction ◽  
Capacitively Coupled ◽  
Swap Gate ◽  
Flux Qubits ◽  
Superconducting Flux Qubits ◽  
Quantum Error ◽  
At Home

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.

scholarly journals Breakdown of Counterflow Superfluidity in a Disordered Quantum Hall Bilayer

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
D. K. K. Lee ◽  
P. R. Eastham ◽  
N. R. Cooper
Keyword(s):  
Critical Current ◽  
Filling Factor ◽  
Quantum Hall ◽  
System Size ◽  
Two Dimensions ◽  
Phase Model ◽  
Superfluid Phase ◽  
Disordered Phase ◽  
Phase Slips ◽  
Coherent Tunneling

We present a theory for the regime of coherent interlayer tunneling in a disordered quantum Hall bilayer at total filling factor one, allowing for the effect of static vortices. We find that the system consists of domains of polarized superfluid phase. Injected currents introduce phase slips between the polarized domains which are pinned by disorder. We present a model of saturated tunneling domains that predicts a critical current for the breakdown of coherent tunneling that is extensive in the system size. This theory is supported by numerical results from a disordered phase model in two dimensions. We also discuss how our picture might be used to interpret experiments in the counterflow geometry and in two-terminal measurements.

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

2014 ◽  
Vol 28 (14) ◽  
pp. 1450081 ◽  
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.

scholarly journals Galvanic Phase Coupling of Superconducting Flux Qubits

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.

scholarly journals Consistency of Ground State and Spectroscopic Measurements on Flux Qubits

2008 ◽  
Vol 101 (1) ◽  
Author(s):  
A. Izmalkov ◽  
S. H. W. van der Ploeg ◽  
S. N. Shevchenko ◽  
M. Grajcar ◽  
E. Il’ichev ◽  
...  
Keyword(s):  
Ground State ◽  
Spectroscopic Measurements ◽  
Flux Qubits

Quantum Measurements of Charge and Flux Qubits

2002 ◽  
pp. 353-363 ◽  
Author(s):  
Yuriy Makhlin ◽  
Gerd SchöN ◽  
Alexander Shnirman
Keyword(s):  
Quantum Measurements ◽  
Flux Qubits

scholarly journals Quantum annealing with capacitive-shunted flux qubits

2020 ◽  
Vol 59 (SG) ◽  
pp. SGGI06
Author(s):  
Yuichiro Matsuzaki ◽  
Hideaki Hakoshima ◽  
Yuya Seki ◽  
Shiro Kawabata
Keyword(s):  
Quantum Annealing ◽  
Flux Qubits

scholarly journals Modeling of macroscopic quantum states in functional properties of the laser-induced 4D-topological nanoclusters in thin films on solid surface

2019 ◽  
Vol 220 ◽  
pp. 01002
Author(s):  
S.M. Arakelian ◽  
A.O. Kucherik ◽  
T.A. Khudaberganov ◽  
D.N. Bukharov
Keyword(s):  
Thin Films ◽  
Lattice Structure ◽  
Wave Length ◽  
Spatial Period ◽  
Nanoparticle Distribution ◽  
De Broglie Wave ◽  
Different Types ◽  
Quantum Behavior ◽  
New Type ◽  
Coherent Tunneling

Nanocluster structures can be easily modified in necessary direction and by controlled way in femtonanophotonics experiments. The variation of the key topology parameters can result in new type of the quantum correlation states/size effect for charged particles. In our earlier experiments we studied laser-induced topological nanoclusters structures of different types in thin films with unique phenomena in electrophysics and optics (see [1-3]). A simple 2-steps mechanism for enhancement of quantum behavior (e.g. in electroconductivity) exists for different conditions. First, when inelastic length linelastic > acluster we have no incoherent electron-phonon (e-ph) scattering, i.e. the coherent process takes place. Second, when de Broglie wave length λdB ≡ ℓcoh < Λ, (acluster – cluster size , Λ – spatial period of nanoparticle distribution) the coherent tunneling without loss occurs, and a long-range order with interference of the states takes place in the medium due to lattice structure.

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