A5024464852- Physics of Superconductivity and Magnetism
- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Quantum Computing Algorithms and Architecture
- 2D Materials and Applications
- Iron-based superconductors research
- Quantum many-body systems
- Advanced Condensed Matter Physics
- Superconducting and THz Device Technology
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- Magnetic and transport properties of perovskites and related materials
- Quantum Mechanics and Applications
- Advanced Fiber Laser Technologies
- Surface and Thin Film Phenomena
- Advanced Frequency and Time Standards
- Rare-earth and actinide compounds
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Electronic and Structural Properties of Oxides
- Nonlinear Photonic Systems
- Laser-Matter Interactions and Applications
- Graphene research and applications
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Chemical Physics Studies
Zhejiang University of Technology
2019-2024
Wuhan University of Science and Technology
2024
Collaborative Innovation Center of Advanced Microstructures
2017-2023
Nanjing University
2010-2023
Zhejiang University
2013-2023
University of Amsterdam
2023
University of Science and Technology of China
2001-2021
Hefei Institutes of Physical Science
2021
High Magnetic Field Laboratory
2001-2021
Chinese Academy of Sciences
2021
We demonstrate a planar, tunable superconducting qubit with energy relaxation times up to $44\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$. This is achieved by using geometry designed both minimize radiative loss and reduce coupling materials-related defects. At these levels of coherence, we find fine structure in the lifetime as function frequency, indicating presence sparse population incoherent, weakly coupled two-level elucidate this defect physics experimentally varying model analysis....
The von Neumann architecture for a classical computer comprises central processing unit and memory holding instructions data. We demonstrate quantum that exchanges data with random-access integrated on chip, stored computer. test our machine by executing codes involve seven elements: Two superconducting qubits coupled through bus, two memories, zeroing registers. vital algorithms computing are demonstrated, the Fourier transform, 66% process fidelity, three-qubit Toffoli-class OR phase gate,...
We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 10 million at high powers over 1 low powers, best power results approaching 2 million, corresponding to ~1 photon in resonator. These are achieved by controllably producing very smooth clean interfaces between resonators' aluminum metallization underlying single crystal sapphire substrate. Additionally, we a method for analyzing resonator response, which can directly...
We find that stray infrared light from the 4 K stage in a cryostat can cause significant loss superconducting resonators and qubits. For devices shielded only metal box, we measured with quality factors Q = 10^5 qubits energy relaxation times T_1=120 ns, consistent light-induced quasiparticle density of 170-230 \mu m^{-3}. By adding second black shield at sample temperature, found about an order magnitude improvement performance no sensitivity to radiation. also tested various shielding...
We present an atomic resolution scanning tunneling spectroscopy study of superconducting ${\mathrm{BaFe}}_{1.8}{\mathrm{Co}}_{0.2}{\mathrm{As}}_{2}$ single crystals in magnetic fields up to 9 T. At zero field, a gap with coherence peaks at $\overline{\ensuremath{\Delta}}=6.25\text{ }\text{ }\mathrm{meV}$ is observed the density states. and 6 T, we image disordered vortex lattice, consistent isotropic, flux quantum vortices. Vortex locations are uncorrelated strong-scattering surface...
Quantum entanglement, one of the defining features quantum mechanics, has been demonstrated in a variety nonlinear spinlike systems. entanglement linear systems proven significantly more challenging, as intrinsic energy level degeneracy associated with linearity makes control difficult. Here we demonstrate photon states two independent microwave resonators, creating $N$-photon NOON (entangled $|N0⟩+|0N⟩$) benchmark demonstration. We use superconducting circuit that includes Josephson qubits...
We demonstrate a superconducting resonator with variable coupling to measurement transmission line. The can be adjusted through zero photon emission rate 1000 times the intrinsic decay rate. catch and release of photons in resonator, as well control nonclassical Fock states. also dynamical waveform from key functionality that will enable high-fidelity quantum state transfer between distant resonators or qubits.
Losses in superconducting planar resonators are presently assumed to predominantly arise from surface-oxide dissipation, due experimental losses varying with choice of materials. We model and simulate the magnitude loss interface surfaces resonator investigate dependence on power, geometry, dimensions. Surprisingly, dominant surface is found metal-substrate substrate-air interfaces. This result will be useful guiding device optimization, even conventional
The unclear relationship between cuprate superconductivity and the pseudogap state remains an impediment to understanding high transition temperature (Tc) superconducting mechanism. Here we employ magnetic-field-dependent scanning tunneling microscopy provide phase-sensitive proof that d-wave coexists with on antinodal Fermi surface of overdoped cuprate. Furthermore, by tracking hole doping (p) dependence quasiparticle interference pattern within a single Bi-based family, observe...
We demonstrate a high-efficiency deterministic quantum receiver to convert flying qubits stationary qubits. employ superconducting resonator, which is driven with shaped pulse through an adjustable coupler. For the ideal ``time-reversed'' shape, we measure absorption and fidelities at single microwave photon level of, respectively, 99.41% 97.4%. These are comparable gates measurement exceed communication computation fault-tolerant thresholds, enabling new designs of qubit interconnects...
The cuprate high-temperature superconductors exhibit many unexplained electronic phases, but it was often thought that the superconductivity at sufficiently high doping is governed by conventional mean-field Bardeen-Cooper-Schrieffer (BCS) theory[1]. However, recent measurements show number of paired electrons (the superfluid density) vanishes when transition temperature Tc goes to zero[2], in contradiction expectation from BCS theory. origin this anomalous vanishing unknown. Our scanning...
We experimentally demonstrate quantum process tomography of controlled-Z and controlled-NOT gates using capacitively coupled superconducting phase qubits. These are realized by the $|2⟩$ state qubit. obtain a fidelity 0.70 for controlled 0.56 gate, with loss mostly due to single-qubit decoherence. The gate is also used two-qubit Deutsch-Jozsa algorithm single function query.
Quasiparticles are an important decoherence mechanism in superconducting qubits, and can be described with a complex admittance that is generalization of the Mattis-Bardeen theory. By injecting nonequilibrium quasiparticles tunnel junction, we verify qualitatively expected change decay rate transition frequency phase qubit. With their relative agreement to within 4 % prediction, theory reliably used infer quasiparticle density. We describe how settling may allow determination whether qubit...
We present a systematic study of the properties room temperature deposited TiN films by varying deposition conditions in an ultra-high-vacuum reactive magnetron sputtering chamber. By increasing pressure from 2 to 9 mTorr while keeping nearly stoichiometric composition Ti1−xNx (x = 0.5) without substrate heating, film resistivity increases, dominant crystal orientation changes (100) (111), grain boundaries become clearer, and strong compressive in-plane strain weak tensile strain. The absorb...
New theoretical proposals and experimental findings on transition metal dichalcogenide 1T-TaS$_2$ have revived interests in its possible Mott insulating state. We perform a comprehensive scanning tunneling microscopy spectroscopy experiment different single-step areas pristine 1T-TaS$_2$. After accurately determining the relative displacement of Star-of-David super-lattices two layers, we find stacking orders can correspond to similar large-gap spectrum upper terrace. When measurement is...
We measure the dependence of qubit phase coherence and flux noise on inductor loop geometry. While wider traces change neither power spectrum nor dephasing time, increased inductance leads to a simultaneous increase in both. Using our new tomographic protocol for measuring low frequency noise, we make direct comparison between decay, finding agreement within 10% theory.
Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that "hot" with energies above the superconducting gap, affect differently from quasiparticles at implying can dynamic quasiparticle energy distribution. For hot we predict a non-negligible increase in qubit excited state probability Pe. By injecting into qubit, experimentally measure Pe semiquantitative agreement model and rule out typically assumed thermal
The nodal-line semimetals have attracted immense interest due to the unique electronic structures such as linear dispersion and vanishing density of states Fermi energy approaching nodes. Here, we report temperature-dependent transport scanning tunneling microscopy (spectroscopy) [STM(S)] measurements on semimetal ZrSiSe. Our experimental results theoretical analyses consistently demonstrate that temperature induces Lifshitz transitions at 80 106 K in ZrSiSe, which anomalies same...
Based on a 'shortcut-to-adiabaticity' (STA) scheme, we theoretically design and experimentally realize set of high-fidelity single-qubit quantum gates in superconducting Xmon qubit system. Through precise microwave control, the is driven to follow fast 'adiabatic' trajectory with assistance counter-diabatic field correction derivative removal by adiabatic gates. The experimental measurements process tomography interleaved randomized benchmarking show that fidelities our STA are higher than...
With a counter-diabatic field supplemented to the reference control field, "shortcut adiabaticiy" (STA) protocol is implemented in superconducting phase qubit. The Berry measured short time scale good agreement with theoretical result acquired from an adiabatic loop. trajectory of qubit vector extracted, verifying alternatively by integrated solid angle. classical noise introduced amplitude or total field. mean under either almost equal that without noise, while variance can be described...