arXiv subjects

Yi-Xuan Wu

Publications and source records attributed to Yi-Xuan Wu.

3 recordsLinked to original sources

arXiv2024

Exact quantum dynamics for two-level systems with time-dependent driving

It is well-known that time-dependent Schrödinger equation can only be exactly solvable in very rare cases, even for two-level quantum systems. Therefore, finding exact quantum dynamics under time-dependent Hamiltonian is not only of fundamental importance in quantum physics but also can facilitate active quantum manipulations for quantum information processing. Here, we present a method which could generate a near infinite number of analytical-assisted solutions of the Schrödinger equation for a qubit with time-dependent driving. This analytical-assisted solution has free parameters with only boundary restrictions, and thus can find many applications in precise quantum manipulations. Due to the general form of the time-dependent Hamiltonian in our scheme, it can be readily implemented in various experimental setups of qubits. Therefore, our scheme provides new solutions for Schrödinger equation, thus provides an alternative and analytical-based routine for precise control over qubits.

quant-ph↗

arXiv2022

Fast quantum state transfer and entanglement for cavity-coupled many qubits via dark pathways

Quantum state transfer (QST) and entangled state generation (ESG) are important building blocks for modern quantum information processing. To achieve these tasks, convention wisdom is to consult the quantum adiabatic evolution, which is time-consuming, and thus is of low fidelity. Here, using the shortcut to adiabaticity technique, we propose a general method to realize high-fidelity fast QST and ESG in a cavity-coupled many qubits system via its dark pathways, which can be further designed for high-fidelity quantum tasks with different optimization purpose. Specifically, with a proper dark pathway, QST and ESG between any two qubits can be achieved without decoupling the others, which simplifies experimental demonstrations. Meanwhile, ESG among all qubits can also be realized in a single step. In addition, our scheme can be implemented in many quantum systems, and we illustrate its implementation on superconducting quantum circuits. Therefore, we propose a powerful strategy for selective quantum manipulation, which is promising in cavity coupled quantum systems and could find many convenient applications in quantum information processing.

quant-ph↗

arXiv2022

Experimental Demonstration of Swift Analytical Universal Control over Nearby Transitions

Along with the scaling of dimensions in quantum systems, transitions between the system's energy levels would become close in frequency, which are conventionally resolved by weak and lengthy pulses. Here, we extend and experimentally demonstrate analytically based swift quantum control techniques on a four-level trapped ion system, where we perform individual or simultaneous control over two pairs of spectrally nearby transitions with tailored time-varied drive, achieving operational fidelities ranging from 99.2(3)\% to 99.6(3)\%. Remarkably, we achieve approximately an order of magnitude speed up comparing with the case of weak square pulse for a general control. Therefore, our demonstration may be beneficial to a broad range of quantum systems with crowded spectrum, for spectroscopy, quantum information processing and quantum simulation.

quant-ph↗