相关论文: Quantum Bit Behavior of Pinned Fluxes on Volume De…

Whereas there are two critical fields that are H$_{c1}$ and H$_{c2}$ in the ideal type II superconductor, there is another critical field H$_{c1}'$ defined as the field showing the maximum diamagnetic property in the real type II…

We have studied flux-pinning effects of MgB$_2$ superconductor by doping (Fe, Ti) particles of which radius is 163 nm on average. 5 wt.\% (Fe, Ti) doped MgB$_2$ among the specimens showed the best field dependence of magnetization and 25…

According to Ginzburg-Landau theory, it has been generally accepted that the diamagnetic property decreases after the lower critical field. However, we found that (Fe, Ti) particle doped MgB2 specimens reveal the Delta H = Delta B section…

Superconducting, flux-based qubits are promising candidates for the construction of a large scale quantum computer. We present an explicit quantum mechanical calculation of the coherent behavior of a flux based quantum bit in a noisy…

We calculate the degree of flux pinning by defects in model high-temperature superconductors (HTSC's). The HTSC is modeled as a three-dimensional network of resistively-shunted Josephson junctions in an external magnetic field,…

The microscopic origin of $1/f$ magnetic flux noise in superconducting circuits has remained an open question for several decades despite extensive experimental and theoretical investigation. Recent progress in superconducting devices for…

We study the quantum operation of coupled superconducting flux qubits under a microwave irradiation. The flux qubits can be described as magnetic dipole moments in the limit of weak microwave field amplitude consistent with usual…

We experimentally demonstrate the coherent oscillations of a tunable superconducting flux qubit by manipulating its energy potential with a nanosecond-long pulse of magnetic flux. The occupation probabilities of two persistent current…

We studied a method of measuring upper critical field (H$_{c2}$) of a superconductor based on the width of $\Delta$H = $\Delta$B region, which appears in the superconductor that volume defects are many and dominant. Here we present the…

We present a systematic study of the phase-coherent dynamics of a superconducting three-Josephson-junction flux qubit. The qubit state is detected with the integrated-pulse method, which is a variant of the pulsed switching DC SQUID method.…

Superconductors exhibit dissipationless supercurrents even under finite bias and magnetic field conditions, provided these remain below the critical values. However, type-II superconductors in the flux flow regime display Ohmic dissipation…

Strong pinning of superconducting flux quanta by a square array of 1 $\mu$m-sized ferromagnetic dots in a magnetic-vortex state was visualized by low-temperature magnetic force microscopy (LT-MFM). A direct correlation of the…

The possibility of making a flux qubit on nonsuperconducting mesoscopic ballistic quasi 1D ring is discussed. We showed that such ring can be effectively reduced to a two-state system with two external control parameters. The two states…

Current superconducting quantum processors require strategies for coping with material defects and imperfect parameter targeting in order to scale up while maintaining high performance. To that end, in-situ control of qubit frequencies with…

Fast tuning of the transition frequency of superconducting qubits using magnetic flux is essential, for example, for realizing high-fidelity two-qubit gates with low leakage or for reducing errors in dispersive qubit readout. To apply…

Superconducting qubits with in-situ tunable properties are important for constructing a quantum computer. Qubit tunability, however, often comes at the expense of increased noise sensitivity. Here, we propose a flux-tunable superconducting…

We have observed coherent time evolution between two quantum states of a superconducting flux qubit comprising three Josephson junctions in a loop. The superposition of the two states carrying opposite macroscopic persistent currents is…

We present a microscopic derivation, without electrodynamical assumptions, of $B(x,y,H(t))$, $M(H(t))$, and $J_c(H(t))$, in agreement with experiments on strongly pinned superconductors, for a range of values of the density and strength of…

The magnetic response is a state-defining property of superconductors. The magnetic flux penetrates type-II bulk superconductors by forming quantum vortices when the enclosed magnetic flux is equal to the magnetic flux quantum. The flux…

Single flux quantum (SFQ) circuitry is a promising candidate for a scalable and integratable cryogenic quantum control system. However, the operation of SFQ circuits introduces non-equilibrium quasiparticles (QPs), which are a significant…