Quartic Anharmonicity in Different Spatial Dimensions

四次Blochnium：一种非谐准电荷超导量子比特

The quartic Blochnium: an anharmonic quasicharge superconducting qubit

本文提出一种采用四次超电感器的准电荷超导量子比特设计，通过约瑟夫森结环链在保持对磁通和电荷涨落鲁棒性的同时增强频谱非谐性，以抑制泄漏错误和频率拥挤。

Radial Anharmonic Oscillator: Perturbation Theory, New Semiclassical Expansion, Approximating Eigenfunctions. II. Quartic and Sextic Anharmonicity Cases

In our previous paper I (del Valle--Turbiner, Int. J. Mod. Phys. A34, 1950143, 2019) it was developed the formalism to study the general $D$-dimensional radial anharmonic oscillator with potential $V(r)= \frac{1}{g^2}\,\hat{V}(gr)$. It was based on the Perturbation Theory (PT) in powers of $g$ (weak coupling regime) and in inverse, fractional powers of $g$ (strong coupling regime) in both $r$-space and in $(gr)$-space, respectively. As the result it was introduced - the Approximant - a locally-accurate uniform compact approximation of a wave function. If taken as a trial function in variationa…

未分辨边带区腔光力学中可调谐的机械非简谐性

Tunable anharmonicity in cavity optomechanics in the unresolved sideband regime

针对纳米力学中引入可控强非简谐性的挑战，本文提出在未分辨边带区通过精确调谐腔光力学系统参数，使机械振荡器产生纯四次有效势，并从理论与数值上预测了机械非简谐性在位移谱和腔光场中的可测量印记。

Square-Well Approximation for the Anharmonic and the Double-Well Oscillators

A novel general approximation scheme (NGAS) proposed earlier (ref.2-3) is applied to the problem of the quartic anharmonic (QAHO) and the double-well-oscillator (QDWO) in quantum theory by choosing the infinite square-well-potential in one dimension as the input approximation. The leading order (LO) results obtained for the energy eigen-values are uniformly accurate to within a few percent of the exact results for $arbitrary$ values of the quartic coupling: $λ> 0$ and the level-index $n_s$. These results are shown to be non-perturbative in the LO and reproduce the known analytic and scaling pr…

Suppressing chaos with mixed superconducting qubit devices

In quantum information processing, a tension between two different tasks occurs: while qubits' states can be preserved by isolating them, quantum gates can be realized only through qubit-qubit interactions. In arrays of qubits, weak coupling leads to states being spatially localized and strong coupling to delocalized states. Here, we study the average energy level spacing and the relative entropy of the distribution of the level spacings (Kullback-Leibler divergence from Poisson and Gaussian Orthogonal Ensemble) to analyze the crossover between localized and delocalized (chaotic) regimes in li…

Circuit Complexity as a novel probe of Quantum Entanglement: A study with Black Hole Gas in arbitrary dimensions

In this article, we investigate the quantum circuit complexity and entanglement entropy in the recently studied black hole gas framework using the two-mode squeezed states formalism written in arbitrary dimensional spatially flat cosmological Friedmann-Lema$\hat{i}$tre-Robertson-Walker (FLRW) background space-time. We compute the various complexity measures and study the evolution of these complexities by following two different prescriptions viz. Covariant matrix method and Nielsen's method. Independently, using the two-mode squeezed states formalism we also compute the Rényi and Von-Neumann …