A5076455505- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Quantum Computing Algorithms and Architecture
- Quantum Mechanics and Applications
- Spectroscopy and Quantum Chemical Studies
- Quantum optics and atomic interactions
- Advanced Thermodynamics and Statistical Mechanics
- Cold Atom Physics and Bose-Einstein Condensates
- stochastic dynamics and bifurcation
- Rare-earth and actinide compounds
- Mechanical and Optical Resonators
- Semiconductor materials and devices
- Superconducting and THz Device Technology
- Surface and Thin Film Phenomena
- Semiconductor Quantum Structures and Devices
- Atomic and Subatomic Physics Research
- Iron-based superconductors research
- Welding Techniques and Residual Stresses
- Advanced Electrical Measurement Techniques
- Electronic and Structural Properties of Oxides
- Neural Networks and Reservoir Computing
- Quantum many-body systems
- Magnetic Field Sensors Techniques
- Molecular Junctions and Nanostructures
Chinese Academy of Sciences
2014-2024
Aerospace Information Research Institute
2024
State Key Laboratory of Transducer Technology
2024
University of Chinese Academy of Sciences
2024
Shanghai Jiao Tong University
2021-2023
Collaborative Innovation Centre for Advanced Ship and Deep-Sea Exploration
2021-2022
University of Kansas
2011-2021
University of Hong Kong
2018-2021
Hong Kong University of Science and Technology
2018-2021
Institute of Physics
2014-2018
We report the generation and observation of coherent temporal oscillations between macroscopic quantum states a Josephson tunnel junction by applying microwaves with frequencies close to level separation. Coherent excited state populations were observed monitoring junction's tunneling probability as function time. From data, lower limit phase decoherence time was estimated be about 5 microseconds.
Here we report on the production and tomography of genuinely entangled Greenberger-Horne-Zeilinger states with up to 10 qubits connecting a bus resonator in superconducting circuit, where resonator-mediated qubit-qubit interactions are used controllably entangle multiple operate different pairs parallel. The resulting 10-qubit density matrix is unambiguously probed, fidelity $0.668 \pm 0.025$. Our results demonstrate largest entanglement created so far solid-state architectures, pave way...
We present a scheme to achieve maximally entangled states, controlled phase-shift gate, and SWAP gate for two superconducting-quantum-interference-device (SQUID) qubits, by placing SQUIDs in microwave cavity. also show how transfer quantum information from one SQUID qubit another. In this scheme, no of between the cavity is required, field only virtually excited thus requirement on quality factor greatly relaxed.
We present a way to teleport multiqubit quantum information from sender distant receiver via the control of many agents in network. show that original state each qubit can be restored by as long all collaborate. However, even if one agent does not cooperate, cannot fully recover qubit. The method operates essentially through entangling during teleportation, such required auxiliary resources, local operation, and classical communication are considerably reduced for purpose.
We report the first observation of resonant tunneling a system between two macroscopically distinct states: energy levels in different fluxoid wells weakly damped superconducting quantum interference device which differ mean current by approximately 6 \ensuremath{\mu}A. Near 50 mK, rate $\ensuremath{\gamma}({\ensuremath{\Phi}}_{x})$ from metastable well vs applied flux ${\ensuremath{\Phi}}_{x}$ is found to exhibit series local maxima where (spaced $\ensuremath{\approx}1.9$ K) cross. The...
We investigate the experimental feasibility of realizing quantum information transfer (QIT) and entanglement with SQUID qubits in a microwave cavity via dark states. Realistic system parameters are presented. Our results show that QIT two-SQUID can be achieved high fidelity. The present scheme is tolerant to device parameter nonuniformity. also strong coupling limit cavity. Thus, cavity-SQUID systems provide new way for production nonclassical source communication.
A rf--superconducting quantum interference device (SQUID) flux qubit that is robust against fabrication variations in Josephson-junction critical currents and inductance has been implemented. Measurements of the persistent current tunneling energy between two lowest-lying states, both coherent incoherent regimes, are presented. These experimental results shown to be agreement with predictions a quantum-mechanical Hamiltonian whose parameters were independently calibrated, thus justifying...
Coupled chemical–mechanical defibrillation and self-assembly processes have been successfully established for creating super-fine (125–497 nm wide) highly crystalline (63.2–71.5% CrI) cellulose Iβ fibrous materials from rice straw cellulose. Under the optimized TEMPO mediated oxidation with 5 mmol g−1 NaClO/cellulose followed by 30 min mechanical blending, uniform (2.09 wide, 1.52 thick, up to 1 μm long) nanofibrils (CNFs) were efficiently derived at an impressive 96.8% yield contained 1.29...
We report the experimental observation of high-order sideband transitions at single-photon level in a quantum circuit system flux qubit ultrastrongly coupled to coplanar waveguide resonator. With coupling strength reaching 10% resonator's fundamental frequency, we obtain clear signatures higher order red-sideband and first-order blue-sideband transitions, which are mainly due ultrastrong Rabi coupling. Our advances understanding systems paves way study processes model level.
Recently, Blockchain becomes a hot research topic due to the success of in many applications, such as cryptocurrency, smart contract, digital assets, distributed cloud storage and so on. The power is that it can achieve consensus an ordered set transactions among nodes which do not trust each other, even with existence malicious nodes. However, compared traditional databases, current technology still cannot handle massive number transactions, caused by factors, protocol, structure blocks...
Coherent control of quantum states is at the heart implementing solid-state processors and testing mechanics macroscopic level. Despite significant progress made in recent years controlling single- bi-partite systems, coherent wave function multipartite systems involving artificial qubits has been hampered due to relatively short decoherence time lacking precise methods. Here we report creation manipulation a tripartite system, which formed by superconducting qubit coupled two microscopic...
We discuss how to generate entangled coherent states of four \textrm{microwave} resonators \textrm{(a.k.a. cavities)} coupled by a superconducting qubit. also show \textrm{that} GHZ state qubits embedded in different \textrm{can be created with this scheme}. In principle, \textrm{the proposed method} can extended create an $n$ and prepare Greenberger-Horne-Zeilinger (GHZ) distributed over cavities quantum network. addition, it is noted that coupler qubit may used as basic circuit block build...
We propose an efficient method to generate a GHZ entangled state of n photons in microwave cavities (or resonators) via resonant interaction single superconducting qutrit. The deployment qutrit, instead qubit, as the coupler enables us use interactions exclusively for all qutrit-cavity and qutrit-pulse operations. This unique approach significantly shortens time operation which is advantageous reducing adverse effects qutrit decoherence cavity decay on fidelity protocol. Furthermore,...
Stimulated Raman adiabatic passage (STIRAP) offers significant advantages for coherent population transfer between un- or weakly-coupled states and has the potential of realizing efficient quantum gate, qubit entanglement, information transfer. Here we report on realization STIRAP in a superconducting phase qutrit - ladder-type system which ground state is coherently transferred to second-excited via dark subspace. The result agrees well with numerical simulation master equation, further...
Anyons are exotic quasiparticles obeying fractional statistics, whose behavior can be emulated in artificially designed spin systems. Here we present an experimental emulation of creating anyonic excitations a superconducting circuit that consists four qubits, achieved by dynamically generating the ground and excited states toric code model, i.e., four-qubit Greenberger-Horne-Zeilinger states. The braiding is implemented via single-qubit rotations: phase shift π related to braiding, hallmark...
Single electron traps have been shown to hold a single charge for over 2 h at 50 mK (limited by observation time). The traps, each with an array of seven Al/${\mathrm{AlO}}_{\mathit{x}}$/Al tunnel junctions normal state resistance R\ensuremath{\sim}300 k\ensuremath{\Omega}, and capacitance, C\ensuremath{\sim}0.15 F, trapped electrons the in both superconducting states. temperature dependence escape time has measured one trap near 0.35 K observed follow Arrhenius law energy barrier...
We present a way to realize an $n$-qubit controlled phase gate with superconducting quantum-interference devices (SQUIDs) by coupling them resonator. In this proposal, the two logical states of qubit are represented lowest levels SQUID. An intermediate level each SQUID is utilized facilitate coherent control and manipulation quantum qubits. It interesting note that can be achieved $n$ SQUIDs successively applying $\ensuremath{\pi}∕2$ Jaynes-Cummings pulse $n\ensuremath{-}1$ before after...
An improved tunable coupling element for building networks of coupled rf-SQUID flux qubits has been experimentally demonstrated. This new form coupler, based upon the compound Josephson junction rf-SQUID, provides a sign and magnitude mutual inductance between with minimal nonlinear crosstalk from coupler tuning parameter into qubits. Quantitative agreement is shown an effective one-dimensional model coupler's potential measurements persistent current susceptibility.
We propose an approach to realize $n$-qubit controlled-$U$ gate with superconducting quantum interference devices (SQUIDs) in cavity QED. In this approach, the two lowest levels of a SQUID represent logical states qubit while higher-energy intermediate level serves manipulation. Our method operates essentially by creating single photon through one control SQUIDs and then performing arbitrary unitrary transformation on target assistance photon. addition, we show that can be applied implement...
The Josephson ${I}_{c}$ between a Ta-wire probe and an induced, surface, singlet, superconducting state in U${\mathrm{Be}}_{13}$ decreases with decreasing temperature below the bulk ${T}_{c}$, contrast to increase seen comparison Mo samples. This shows that superconductivity suppresses induced singlet superconductivity. Such suppression is evidence of triplet super-conducting U${\mathrm{Be}}_{13}$. Evidence presented for phase slip weakly coupled order parameters.
We present a Floquet treatment of multiphoton quantum interference in strongly driven superconducting flux qubit. The periodically time-dependent Schr\"odinger equation can be reduced to an equivalent time-independent infinite-dimensional matrix eigenvalue problem. For resonant or nearly transitions, we extend the generalized Van Vleck (GVV) degenerate high-order perturbation theory for Hamiltonian, allowing reduction $N\ifmmode\times\else\texttimes\fi{}N$ effective where $N$ is number...
Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in flux qubit. Measurements incoherent decay rate as function bias revealed Gaussian-shaped profile that not peaked at resonance point but shifted which initial well higher than target well. The rms amplitude noise, proportional dephasing 1/tauphi, was observed be weakly dependent on temperature below 70 mK. Analysis these results indicates dominant source low energy this...
Abstract The Kibble-Zurek mechanism (KZM) predicts the density of topological defects produced in dynamical processes phase transitions systems ranging from cosmology to condensed matter and quantum materials. similarity between KZM Landau-Zener transition (LZT), which is a standard tool describe dynamics some non-equilibrium physics contemporary physics, being extensively exploited. Here we demonstrate equivalence Ising model LZT superconducting qubit system. We develop time-resolved...
We determined the dissipation-induced decoherence time (DIDT) of a superconducting Josephson tunnel junction by time-resolved measurements its escape dynamics. Double-exponential behavior time-dependent probability was observed, suggesting occurrence two-level decay-tunneling process in which energy relaxation from excited to ground level significantly affects dynamics system. The observation temporal double-exponential dependence enables direct DIDT, property critical study quantum and...
A submillimeter wave source based on a new design using Josephson junction arrays has been developed and tested. The maximum rf power, delivered to 68Ω load detected chip, was 47 μW at 394 GHz. Significant power number of frequencies from 300 500 GHz where the 10 μW. observed designed operating frequency near 400 is consistent with all junctions in series biased array delivering current phase loads. This agreement simulations smaller same design. linewidth, inferred measured resistance point...