Zijun Chen
A5101609780- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Data Management and Algorithms
- Geographic Information Systems Studies
- Advancements in Semiconductor Devices and Circuit Design
- Physics of Superconductivity and Magnetism
- Orbital Angular Momentum in Optics
- Perovskite Materials and Applications
- Quantum many-body systems
- Neural Networks and Reservoir Computing
- Photonic and Optical Devices
- Luminescence Properties of Advanced Materials
- Gyrotron and Vacuum Electronics Research
- Advanced Mathematical Physics Problems
- Metamaterials and Metasurfaces Applications
- Particle accelerators and beam dynamics
- Automated Road and Building Extraction
- Advanced Antenna and Metasurface Technologies
- GaN-based semiconductor devices and materials
- Plasmonic and Surface Plasmon Research
- Microwave Engineering and Waveguides
- Semiconductor materials and devices
- Advanced Sensor and Energy Harvesting Materials
- Energy Efficient Wireless Sensor Networks
University of Science and Technology of China
2020-2025
Peking University
2025
Yanshan University
2010-2024
Guangxi University
2024
Google (United States)
2018-2024
Dalian Medical University
2024
Chongqing Medical University
2024
Second Affiliated Hospital of Chongqing Medical University
2024
Xiamen University of Technology
2021-2024
Ocean University of China
2024
As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations fermionic systems remain one most promising directions. Here, we perform a series chemistry largest which involved dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model binding energy ${\rm H}_6$, H}_8$, H}_{10}$ H}_{12}$ chains as well isomerization diazene. also demonstrate error-mitigation strategies based on $N$-representability dramatically improve effective...
Realizing the potential of quantum computing requires sufficiently low logical error rates1. Many applications call for rates as 10-15 (refs. 2-9), but state-of-the-art platforms typically have physical near 10-3 10-14). Quantum correction15-17 promises to bridge this divide by distributing information across many qubits in such a way that errors can be detected and corrected. Errors on encoded qubit state exponentially suppressed number grows, provided are below certain threshold stable...
Quantum algorithms offer a dramatic speedup for computational problems in material science and chemistry. However, any near-term realizations of these will need to be optimized fit within the finite resources offered by existing noisy hardware. Here, taking advantage adjustable coupling gmon qubits, we demonstrate continuous two-qubit gate set that can provide threefold reduction circuit depth as compared standard decomposition. We implement two families: an imaginary swap-like (iSWAP-like)...
Abstract Quantum many-body systems display rich phase structure in their low-temperature equilibrium states 1 . However, much of nature is not thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium can exhibit novel dynamical phases 2–8 may otherwise be forbidden by thermodynamics, a paradigmatic example being the discrete time crystal (DTC) 7,9–15 Concretely, defined periodically driven many-body-localized (MBL) via concept eigenstate order 7,16,17 In...
Interaction in quantum systems can spread initially localized information into the many degrees of freedom entire system. Understanding this process, known as scrambling, is key to resolving various conundrums physics. Here, by measuring time-dependent evolution and fluctuation out-of-time-order correlators, we experimentally investigate dynamics scrambling on a 53-qubit processor. We engineer circuits that distinguish two mechanisms associated with operator spreading entanglement, observe...
Leakage errors occur when a quantum system leaves the two-level qubit subspace. Reducing these is critically important for error correction to be viable. To quantify leakage errors, we use randomized benchmarking in conjunction with measurement of population. We characterize single gates superconducting qubit, and by refining our derivative reduction adiabatic gate pulse shaping along detuning pulses, obtain consistently below 10^{-3} rates at 10^{-5} level. With control optimized, find that...
Many superconducting qubit systems use the dispersive interaction between and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce transitions in if number of photons is too high. We investigate these find they push out two-level subspace, show resonant behavior as function photon number. develop theory for observations based on level crossings within Jaynes-Cummings ladder, with mediated by terms Hamiltonian are...
We present a fabrication process for fully superconducting interconnects compatible with qubit technology. These allow the three dimensional integration of quantum circuits without introducing lossy amorphous dielectrics. They are composed indium bumps several microns tall separated from an aluminum base layer by titanium nitride which serves as diffusion barrier. measure whole structure to be (transition temperature 1.1 K), limited aluminum. have average critical current 26.8 mA, and...
Superconducting microwave circuits based on coplanar waveguides (CPW) are susceptible to parasitic slotline modes which can lead loss and decoherence. We motivate the use of superconducting airbridges as a reliable method for preventing propagation these modes. describe fabrication resonators, we measure due placing over CPW lines. find that additional at single photon levels is small, decreases higher drive powers.
Abstract Actualizing highly efficient solution‐processed thermally activated delayed fluorescent (TADF) organic light‐emitting diodes (OLEDs) at high brightness becomes significant to the popularization of purely electroluminescence. Herein, a soluble emitter benzene‐1,3,5‐triyltris((4‐(9,9‐dimethylacridin‐10(9 H )‐yl)phenyl)methanone was developed, yielding fluorescence rate ( k TADF > 10 5 s −1 ) ascribed multitransition channels and tiny singlet–triplet splitting energy (Δ E ST ≈ 32.7...
Josephson junctions form the essential non-linearity for almost all superconducting qubits. The junction is formed when two electrodes come within $\sim$1 nm of each other. Although capacitance these a small fraction total qubit capacitance, nearby electric fields are more concentrated in dielectric surfaces and can contribute substantially to dissipation. We have developed technique experimentally investigate effect on quality devices. use $\lambda$/4 coplanar waveguide resonators emulate...
Strongly correlated quantum systems give rise to many exotic physical phenomena, including high-temperature superconductivity. Simulating these on computers may avoid the prohibitively high computational cost incurred in classical approaches. However, systematic errors and decoherence effects presented current devices make it difficult achieve this. Here, we simulate dynamics of one-dimensional Fermi-Hubbard model using 16 qubits a digital superconducting processor. We observe separations...
Fast nondemolition measurement of superconducting qubits is important for the operation quantum computers, but readout constrained by measurement-induced state transitions that shift qubit population outside its computational subspace. This work experimentally characterizes phenomenon and provides an intuitive model to explain physical process. Surprisingly, offset charge transmon qubit, which usually ignored, in explaining experiments. These results inform engineering physics-based...
We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device matched to 50 Ω environment with Klopfenstein-taper impedance transformer and achieves bandwidth 250–300 MHz input saturation powers up −95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used benchmark these devices, providing calibration for readout power, estimation added noise, platform comparison against standard...
Measurement is an essential component of quantum algorithms, and for superconducting qubits it often the most error prone. Here, we demonstrate model-based readout optimization achieving low measurement errors while avoiding detrimental side effects. For simultaneous midcircuit measurements across 17 qubits, observe 1.5% per qubit with a 500 ns end-to-end duration minimal excess reset from residual resonator photons. We also suppress measurement-induced state transitions leakage rate limited...
Abstract Design of core–shell structure for ceramic filler is an effective way to improve the electric insulation property polymer matrix. However, it still faces disadvantage a low dielectric constant, inhibiting increase in energy storage density. Herein, we propose strategy regulating shell thickness induce polarization, which simultaneously improves constant and breakdown strength polyvinylidene difluoride (PVDF)‐based nanocomposite incorporated by structured BaTiO 3 @SiO 2 (BT@SO)...
While large-scale fault-tolerant quantum computers promise to enable the solution certain classes of problems for which no other efficient approach is known, such a machine believed require over million performant qubits. Scaling today's 0(100) qubit superconducting (SC) this extent while also improving performance carries many daunting challenges, including control large processor (QP). Integrating electronics at an intermediate temperature stage within cryostat attractive option, e.g., due...