Information free quantum bus for generating stabiliser states

Simple protocol for generating W states in resonator-based quantum computing architectures

We describe a simple, practical scheme for generating multi-qubit W states in resonator-based architectures, in which N Josephson phase qubits are capacitively coupled to a common resonator bus. The entire control sequence consists of three pulses: a local Rabi pulse that excites a single qubit in the circuit; a coupling pulse that transfers the qubit excitation to the resonator bus; and the main, entangling operation that simultaneously couples the bus to all N qubits. If the qubit-resonator coupling strength g is much smaller than the qubit energy splitting, the system initially excited into…

Single-step implementation of the controlled-Z gate in a qubit/bus/qubit device

We propose a simple scheme for generating a high-fidelity controlled-Z (CZ) gate in a three-component qubit/bus/qubit device. The corresponding tune/detune pulse is single-step, with a near-resonant constant undershoot between the 200 and 101 states. During the pulse, the frequency of the first qubit is kept fixed, while the frequency of the second qubit is varied in such a way as to bring the 200 and 101 states close to resonance. As a result, the phase of the 101 state is accumulated via the corresponding second-order anticrossing. For experimentally realistic qubit frequencies and a 75 MHz …

用非稳定性换取非稳定性

Trading athermality for nonstabiliserness

研究通过热浴使初始稳定性态产生非稳定性，推导出必要充分条件，并确定最优生成非稳定性资源的条件和温度。

减少、复用、回收，以实现鲁棒的簇态生成

Reduce, reuse, recycle, for robust cluster state generation

针对大规模基于测量的量子计算中的簇态生成问题，本文提出在物质-光学混合系统中生成小型簇态“乐高积木”并复用辅助总线，以减少操作、抑制退相干并实现可扩展制备。

One-step implementation of entanglement generation on microwave photons in distant 1D superconducting resonators

We present a scalable quantum-bus-based device for generating the entanglement on microwave photons (MPs) in distant superconducting resonators (SRs). Different from the processors in previous works with some resonators coupled to a superconducting qubit (SQ), our device is composed of some 1D SRs $r_j$ which are coupled to the quantum bus (another common resonator $R$) in its different positions simply, assisted by superconducting quantum interferometer devices. By using the technique for catching and releasing a MP state in a 1D SR, it can work as an entanglement generator or a node in quant…

Generation of genuine $χ$-type four-particle entangled state of superconducting artificial atoms with broken symmetry

We propose a scheme for generating a genuine $χ$-type four-particle entangled state of superconducting artificial atoms with broken symmetry by using one-dimensional transmission line resonator as a data bus. The $Δ$-type three-level artificial atom we use in the scheme is different from natural atom and has cyclic transitions. After suitable interaction time and simple operations, the desired entangled state can be obtained. Since artificial atomic excited states and photonic states are adiabatically eliminated, our scheme is robust against the spontaneous emissions of artificial atoms and th…