There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

비만아 부모의 돌봄 경험: q 방법론

By coupling a collection of two-level artificial atoms simultaneously to two superconducting resonators, we propose a quantum switch that can tune the resonator-resonator coupling strength from zero to a large value proportional to the qubit number. This process is realized by preparing the qubits in different pairwise subradiant states, where the microwave photons released by different qubits interfere destructively such that the coupling strength can be stabilized in an open environment. The resulting two-step control scheme tunes the coupling strength between different values in nanoseconds without changing the transition frequency of the qubits. We also use the quantum switch to network multiple resonators with programmable couplings, and we demonstrate its potential applications in quantum simulation and quantum information storage and processing.

Tuning the coupling between superconducting resonators with collective qubits

We propose a hybrid system to realize long information storage and fast quantum operation via Rydberg atoms and superconducting qubits (SCQs). The internal states of a Rydberg atom are coupled to a nanomechanical resonator. The atom-resonator coupling is achieved via an electric field generated by the quantized motions of the resonator and temporarily exciting the atom to Rydberg states. The coupling can be made large enough to allow quantum manipulation and measurement of the resonator via the atom. The resonator can also be coupled to a SCQ, and therefore the tripartite system can provide a quantum interface between the SCQ and the atom via the nanomechanical resonator.

Coupling Rydberg atoms to superconducting qubits via nanomechanical resonator

Topological insulators have inspired the study with various quantum simulators. Exploiting the tunability of the qubit frequency and qubit-qubit coupling, we show that a superconducting qubit chain can simulate various topological band models. When the system is restricted to the single-spin excitation subspace, the Su-Schrieffer-Heeger (SSH) model can be equivalently simulated by alternating the coupling strength between neighboring qubits. The existence of topological edge states in this qubit chain is demonstrated in the quench dynamics after the first qubit is excited. This excitation propagates along the chain where the qubit-qubit coupling is homogeneous. In contrast, in our qubit chain, the spin-up state localizes at the first qubit and the rest qubits remain in the spin-down state. We further show that the spin-up state can be transported along the chain by modulating the coupling strengths and the qubit frequencies. This demonstrates adiabatic pumping based on the Rice-Mele model. Moreover, we also discuss possible ways to construct other topological models with different topological phenomena within the current technology of superconducting qubits.

Topological edge states and pumping in a chain of coupled superconducting qubits

Quantum coherent feedback has been proven to be an efficient way to tune the dynamics of quantum optical systems and, recently, those of solid-state quantum circuits Here, inspired by the recent progress of quantum feedback experiments, especially those in mesoscopic circuits, we prove that superconducting circuit QED systems, shunted with a coherent feedback loop, can change the dynamics of a superconducting transmission line resonator, ie, a linear quantum cavity, and lead to strong on-chip nonlinear optical phenomena We find that bistability can occur under the semiclassical approximation and photon antibunching can be shown in the quantum regime Our study presents alternate perspectives for engineering nonlinear quantum dynamics on a chip

https://dml.riken.jp/images/pdf/PhysRevA.88.063851.pdf

Feedback-induced nonlinearity and superconducting on-chip quantum optics

The nonresonant interaction between the high-density excitons in a quantum well and a single-mode cavity field is investigated. An analytical expression for the physical spectrum of the excitons is obtained. The spectral properties of the excitons, which are initially prepared in the number states or the superposed states of the two different number states by the resonant femtosecond pulse pumping experiment, are studied. A numerical study of the physical spectrum is carried out and a discussion of the detuning effect is presented.

Yu-xi Liu

Papers

Tuning the coupling between superconducting resonators with collective qubits

Coupling Rydberg atoms to superconducting qubits via nanomechanical resonator

Topological edge states and pumping in a chain of coupled superconducting qubits

Feedback-induced nonlinearity and superconducting on-chip quantum optics

Semiconductor-cavity QED in high- Q regimes: Detuning effect