Publications by authors named "Chao-Yang Lu"

The emergence of quantum mechanics and general relativity has transformed our understanding of the natural world significantly. However, integrating these two theories presents immense challenges, and their interplay remains untested. Recent theoretical studies suggest that the single-photon interference covering huge space can effectively probe the interface between quantum mechanics and general relativity.

View Article and Find Full Text PDF
Article Synopsis
  • Fractional quantum Hall (FQH) states have strong topological order, making them promising for fault-tolerant quantum computing applications.
  • Researchers have created a lattice version of photon FQH states using a programmable on-chip platform, demonstrating key properties like the effective photon Lorentz force and chiral topological flow.
  • Their work highlights the potential for creating and manipulating new types of strongly correlated quantum matter with photons, paving the way for advanced quantum information technologies.
View Article and Find Full Text PDF

In the quest to build general-purpose photonic quantum computers, fusion-based quantum computation has risen to prominence as a promising strategy. This model allows a ballistic construction of large cluster states which are universal for quantum computation, in a scalable and loss-tolerant way without feed forward, by fusing many small n-photon entangled resource states. However, a key obstacle to this architecture lies in efficiently generating the required essential resource states on photonic chips.

View Article and Find Full Text PDF

Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated surface code, and further experimentally implement it on the Zuchongzhi 2.

View Article and Find Full Text PDF

We report new Gaussian boson sampling experiments with pseudo-photon-number-resolving detection, which register up to 255 photon-click events. We consider partial photon distinguishability and develop a more complete model for the characterization of the noisy Gaussian boson sampling. In the quantum computational advantage regime, we use Bayesian tests and correlation function analysis to validate the samples against all current classical spoofing mockups.

View Article and Find Full Text PDF

Berry curvature is a fundamental element to characterize topological quantum physics, while a full measurement of Berry curvature in momentum space was not reported for topological states. Here we achieve two-dimensional Berry curvature reconstruction in a photonic quantum anomalous Hall system via Hall transport measurement of a momentum-resolved wave packet. Integrating measured Berry curvature over the two-dimensional Brillouin zone, we obtain Chern numbers corresponding to -1 and 0.

View Article and Find Full Text PDF

Recent breakthroughs have opened the possibility of intermediate-scale quantum computing with tens to hundreds of qubits, and shown the potential for solving classical challenging problems, such as in chemistry and condensed matter physics. However, the high accuracy needed to surpass classical computers poses a critical demand on the circuit depth, which is severely limited by the non-negligible gate infidelity, currently around 0.1%-1%.

View Article and Find Full Text PDF

Complex quantum electronic circuits can be used to design noise-protected qubits, but their complexity may exceed the capabilities of classical simulation. In such cases, quantum computers are necessary for efficient simulation. In this work, we demonstrate the use of variational quantum computing on a transmon-based quantum processor to simulate a superconducting quantum electronic circuit and design a new type of qubit called "Plasmonium", which operates in the plasmon-transition regime.

View Article and Find Full Text PDF

Scalable generation of genuine multipartite entanglement with an increasing number of qubits is important for both fundamental interest and practical use in quantum-information technologies. On the one hand, multipartite entanglement shows a strong contradiction between the prediction of quantum mechanics and local realization and can be used for the study of quantum-to-classical transition. On the other hand, realizing large-scale entanglement is a benchmark for the quality and controllability of the quantum system and is essential for realizing universal quantum computing.

View Article and Find Full Text PDF

The refractive index is a critical parameter in optical and photonic device design. However, due to the lack of available data, precise designs of devices working in low temperatures are still frequently limited. In this work, we have built a homemade spectroscopic ellipsometer (SE) and measured the refractive index of GaAs at a matrix of temperatures (4 K < T < 295 K) and photon wavelengths (700 nm < λ < 1000 nm) with a system error of ∼0.

View Article and Find Full Text PDF

An introduction to the themed collection on emerging quantum technologies at the nanoscale, featuring high-quality research on quantum materials and devices for computing, sensing, imaging and communication.

View Article and Find Full Text PDF

Gaussian boson sampling (GBS) is not only a feasible protocol for demonstrating quantum computational advantage, but also mathematically associated with certain graph-related and quantum chemistry problems. In particular, it is proposed that the generated samples from the GBS could be harnessed to enhance the classical stochastic algorithms in searching some graph features. Here, we use Jiǔzhāng, a noisy intermediate-scale quantum computer, to solve graph problems.

View Article and Find Full Text PDF

Nonlocality arising in networks composed of several independent sources gives rise to phenomena radically different from that in standard Bell scenarios. Over the years, the phenomenon of network nonlocality in the entanglement-swapping scenario has been well investigated and demonstrated. However, it is known that violations of the so-called bilocality inequality used in previous experimental demonstrations cannot be used to certify the nonclassicality of their sources.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Semiconductor quantum dots, as promising solid-state platform, have exhibited deterministic photon pair generation with high polarization entanglement fidelity for quantum information applications. However, due to temporal correlation from inherently cascaded emission, photon indistinguishability is limited, which restricts their potential scalability to multi-photon experiments. Here, by utilizing quantum interferences to decouple polarization entanglement from temporal correlation, we improve four-photon Greenberger-Horne-Zeilinger (GHZ) state entanglement fidelity from (58.

View Article and Find Full Text PDF
Article Synopsis
  • * High-quality N00N states are hard to create and easily damaged by photon loss, limiting their effectiveness for consistent quantum measurements.
  • * The new method combines nonlinear interferometers and squeezed light to achieve a significant 5.8-fold increase in measurement sensitivity without major drawbacks, making it practical for real-world applications in quantum metrology.
View Article and Find Full Text PDF

To ensure a long-term quantum computational advantage, the quantum hardware should be upgraded to withstand the competition of continuously improved classical algorithms and hardwares. Here, we demonstrate a superconducting quantum computing systems Zuchongzhi 2.1, which has 66 qubits in a two-dimensional array in a tunable coupler architecture.

View Article and Find Full Text PDF

Quantum mechanics is commonly formulated in a complex, rather than real, Hilbert space. However, whether quantum theory really needs the participation of complex numbers has been debated ever since its birth. Recently, a Bell-like test in an entanglement-swapping scenario has been proposed to distinguish standard quantum mechanics from its real-valued analog.

View Article and Find Full Text PDF

Networks of optical clocks find applications in precise navigation, in efforts to redefine the fundamental unit of the 'second' and in gravitational tests. As the frequency instability for state-of-the-art optical clocks has reached the 10 level, the vision of a global-scale optical network that achieves comparable performances requires the dissemination of time and frequency over a long-distance free-space link with a similar instability of 10. However, previous attempts at free-space dissemination of time and frequency at high precision did not extend beyond dozens of kilometres.

View Article and Find Full Text PDF

Nonlocality captures one of the counterintuitive features of nature that defies classical intuition. Recent investigations reveal that our physical world's nonlocality is at least tripartite; i.e.

View Article and Find Full Text PDF

Topological insulators host topology-linked boundary states, whose spin and charge degrees of freedom could be exploited to design topological devices with enhanced functionality. We experimentally observe that dissipationless chiral edge states in a spin-orbit coupled anomalous Floquet topological phase exhibit topological spin texture on boundaries, realized via a two-dimensional quantum walk. Our experiment shows that, for a walker traveling around a closed loop along the boundary in real space, its spin evolves and winds through a great circle on the Bloch sphere, which implies that edge-spin texture has nontrivial winding.

View Article and Find Full Text PDF

Quantum error correction is a critical technique for transitioning from noisy intermediate-scale quantum devices to fully fledged quantum computers. The surface code, which has a high threshold error rate, is the leading quantum error correction code for two-dimensional grid architecture. So far, the repeated error correction capability of the surface code has not been realized experimentally.

View Article and Find Full Text PDF

First proposed by Mayers and Yao, self-testing provides a certification method to infer the underlying physics of quantum experiments in a black-box scenario. Numerous demonstrations have been reported to self-test various types of entangled states. However, all the multiparticle self-testing experiments reported so far suffer from both detection and locality loopholes.

View Article and Find Full Text PDF
Article Synopsis
  • Long-distance quantum state transfer (QST) relies on quantum teleportation and involves distant parties, Alice and Bob, communicating through a shared entangled state created by a source, Charlie.
  • Atmospheric turbulence complicates the process of accurately measuring the entangled states as they travel, which traditionally requires local Bell-state measurements by Alice and Charlie.
  • The study showcases a successful long-distance QST over 1200 km using a stable interferometer and satellite technology, achieving an average fidelity of 0.82±0.01 for six distinct quantum states, surpassing the classical limit for qubit transfer.
View Article and Find Full Text PDF

Standard quantum theory was formulated with complex-valued Schrödinger equations, wave functions, operators, and Hilbert spaces. Previous work attempted to simulate quantum systems using only real numbers by exploiting an enlarged Hilbert space. A fundamental question arises: are the complex numbers really necessary in the standard formalism of quantum theory? To answer this question, a quantum game has been developed to distinguish standard quantum theory from its real-number analog, by revealing a contradiction between a high-fidelity multiqubit quantum experiment and players using only real-number quantum theory.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: