18 research outputs found
Superconducting Quantum Computing: A Review
Over the last two decades, tremendous advances have been made for
constructing large-scale quantum computers. In particular, the quantum
processor architecture based on superconducting qubits has become the leading
candidate for scalable quantum computing platform, and the milestone of
demonstrating quantum supremacy was first achieved using 53 superconducting
qubits in 2019. In this work, we provide a brief review on the experimental
efforts towards building a large-scale superconducting quantum computer,
including qubit design, quantum control, readout techniques, and the
implementations of error correction and quantum algorithms. Besides the state
of the art, we finally discuss future perspectives, and which we hope will
motivate further research.Comment: Updated version, Typos corrected, New references added, New
discussions adde
Quantum Neuronal Sensing of Quantum Many-Body States on a 61-Qubit Programmable Superconducting Processor
Classifying many-body quantum states with distinct properties and phases of
matter is one of the most fundamental tasks in quantum many-body physics.
However, due to the exponential complexity that emerges from the enormous
numbers of interacting particles, classifying large-scale quantum states has
been extremely challenging for classical approaches. Here, we propose a new
approach called quantum neuronal sensing. Utilizing a 61 qubit superconducting
quantum processor, we show that our scheme can efficiently classify two
different types of many-body phenomena: namely the ergodic and localized phases
of matter. Our quantum neuronal sensing process allows us to extract the
necessary information coming from the statistical characteristics of the
eigenspectrum to distinguish these phases of matter by measuring only one
qubit. Our work demonstrates the feasibility and scalability of quantum
neuronal sensing for near-term quantum processors and opens new avenues for
exploring quantum many-body phenomena in larger-scale systems.Comment: 7 pages, 3 figures in the main text, and 13 pages, 13 figures, and 1
table in supplementary material
Experimental quantum computational chemistry with optimised unitary coupled cluster ansatz
Simulation of quantum chemistry is one of the most promising applications of
quantum computing. While recent experimental works have demonstrated the
potential of solving electronic structures with variational quantum eigensolver
(VQE), the implementations are either restricted to nonscalable (hardware
efficient) or classically simulable (Hartree-Fock) ansatz, or limited to a few
qubits with large errors for the more accurate unitary coupled cluster (UCC)
ansatz. Here, integrating experimental and theoretical advancements of improved
operations and dedicated algorithm optimisations, we demonstrate an
implementation of VQE with UCC for H_2, LiH, F_2 from 4 to 12 qubits. Combining
error mitigation, we produce high-precision results of the ground-state energy
with error suppression by around two orders of magnitude. For the first time,
we achieve chemical accuracy for H_2 at all bond distances and LiH at small
bond distances in the experiment. Our work demonstrates a feasible path towards
a scalable solution to electronic structure calculation, validating the key
technological features and identifying future challenges for this goal.Comment: 8 pages, 4 figures in the main text, and 29 pages supplementary
materials with 16 figure
TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A spherical acrylic vessel containing 2.8 ton gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full coverage. The photoelectron yield is about 4500 per MeV, an order higher than any existing large-scale liquid scintillator detectors. The detector operates at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The detector will measure about 2000 reactor antineutrinos per day, and is designed to be well shielded from cosmogenic backgrounds and ambient radioactivities to have about 10% background-to-signal ratio. The experiment is expected to start operation in 2022
Measuring low energy atmospheric neutrino spectra with the JUNO detector
Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about Cosmic Rays and neutrino oscillations. The Jiangmen Underground Neutrino Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric and fluxes is presented in this paper. In this study, a sample of atmospheric neutrinos Monte Carlo events has been generated, starting from theoretical models, and then processed by the detector simulation. The excellent timing resolution of the 3" PMT light detection system of JUNO detector and the much higher light yield for scintillation over Cherenkov allow to measure the time structure of the scintillation light with very high precision. Since and interactions produce a slightly different light pattern, the different time evolution of light allows to discriminate the flavor of primary neutrinos. A probabilistic unfolding method has been used, in order to infer the primary neutrino energy spectrum from the detector experimental observables. The simulated spectrum has been reconstructed between 100 MeV and 10 GeV, showing a great potential of the detector in the atmospheric low energy region