Phys.org June 18, 2024 The lack of nonlinearity in photonics has led to encoded measurement-based quantum computing, which relies on linear operations but requires access to resourceful (’nonlinear’) quantum states. In contrast, superconducting microwave circuits offer engineerable nonlinearities but suffer from static Kerr nonlinearity. An international team of researchers (Sweden, Germany) demonstrated universal control of a bosonic mode composed of a superconducting nonlinear asymmetric inductive element (SNAIL) resonator, enabled by native nonlinearities in the SNAIL element. They suppressed static nonlinearities and dynamically activated nonlinearities up to third order by fast flux pulses. They experimentally realized a universal set of generalized […]
Category Archives: Quantum computing
Study of photons in quantum computing reveals that when photons collide, they create vortices
Phys.org June 6, 2024 All-optical generation of photonic vortices requires sufficiently strong nonlinearity that is typically achieved in the classical optics regime. Researchers in Israel realized quantum vortices of photons that resulted from a strong photon-photon interaction in a quantum nonlinear optical medium. The interaction caused faster phase accumulation for copropagating photons, producing a quantum vortex-antivortex pair within the two-photon wave function. For three photons, the formation of vortex lines and a central vortex ring confirmed the existence of a genuine three-photon interaction. The wave function topology, governed by two- and three-photon bound states, imposed a conditional phase shift of […]
The experimental demonstration of a verifiable blind quantum computing protocol
Phys.org April 13, 2024 An international team of researchers (UK, France, USA -University of Maryland) used a trapped-ion quantum server and a client-side photonic detection system networked via a fiber-optic quantum link. The availability of memory qubits and deterministic entangling gates enabled interactive protocols without post selection which previous realizations could not provide. They quantified the privacy at ≲0.03 leaked classical bits per qubit. According to the researchers their experiment demonstrated a path to fully verified quantum computing in the cloud… read more. Open Access TECHNICAL ARTICLE
Scientists launch hub to channel quantum power for good
Phys.org March 5, 2024 The Open Quantum Institute seeks to inclusively unleash the powers of quantum computing to ensure that the whole world contributes to and benefits from quantum computing. While traditional computers process information in bits that can be represented by 0 or 1, quantum computers use qubits, which can be a combination of both at the same time, allowing them to solve more complex problems. The first commercial quantum computers are still believed to be up to a decade away, and the technology is not expected to be fully developed before around 2050. With quantum computing still under […]
Scientists manipulate quantum fluids of light, bringing us closer to next-generation unconventional computing
Phys.org October 31, 2023 An international team of researchers (Russia, UK, Germany) investigated active spatial control of polariton condensates independent of the polariton, gain-inducing excitation profile by introducing an extra intracavity semiconductor layer, nonresonant to the cavity mode. Partial saturation of the optical absorption in the uncoupled layer enabled the ultrafast modulation of the effective refractive index and, through excited-state absorption, the polariton dissipation. Utilizing an intricate interplay of these mechanisms, they demonstrated control over the spatial profile, density, and energy of a polariton condensate at room temperature… read more. TECHNICAL ARTICLE
New quantum computing architecture achieves electron charge qubit with 0.1 millisecond coherence time
Phys.org October 26, 2023 Electron charge qubits built on conventional semiconductors and superconductors suffer from severe charge noise that limits their coherence time to the order of one microsecond. A team of researchers in the US (Argonne National Laboratory, University of Chicago, Lawrence Berkeley National Laboratory, NSF Institute… MA, MIT, Northeastern University, Stanford University, University of Notre Dame) reported electron charge qubits exceeding the charge noise limit, based on isolated single electrons trapped on an ultraclean solid neon surface in a vacuum. Quantum information was encoded in the motional states of an electron that was strongly coupled with microwave photons […]
Illuminating errors creates a new paradigm for quantum computing
Phys.org October 11, 2023 For eventual application in quantum error correction, it is advantageous to realize qubits with structured error models, such as biased Pauli errors or conversion of errors into detectable erasures. An international team of researchers (USA – Princeton University, Yale University, France) demonstrated a new neutral atom qubit using the nuclear spin of a long-lived metastable state in 171Yb. The long coherence time and fast excitation to the Rydberg state allowed one- and two-qubit gates with fidelities of 0.9990(1) and 0.980(1), respectively. A large fraction of all gate errors results in decays out of the qubit subspace […]
Researchers advance topological superconductors for quantum computing
Nanowerk September 21, 2023 The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. A team of researchers in the US (Oak Ridge National Laboratory, Rutgers State University of New Jersey) have shown superconductivity in monolayer (ML) FeTe1–ySey (Fe(Te,Se)) grown on Bi2Te3 by molecular beam epitaxy (MBE). Spin and angle-resolved photoemission spectroscopy (SARPES) directly resolved the interfacial […]
A linear path to efficient quantum technologies
Nanowerk September 12, 2023 Bell-state projections serve as a fundamental basis for most quantum communication and computing protocols today. However, with current Bell-state measurement schemes based on linear optics, only two of four Bell states can be identified, which means that the maximum success probability of this vital step cannot exceed 50%. Researchers in Germany experimentally demonstrated a scheme that amended the original measurement with additional modes in the form of ancillary photons, which led to a more complex measurement pattern, and ultimately a higher success probability of 62.5%. Experimentally, they achieved a success probability of (57.9 ± 1.4)%, a […]
Preparing for a quantum leap: Researchers chart future for use of quantum computing in particle physics
Phys.org July 17, 2023 The rapid development of hardware devices with various realizations of qubits enables the execution of small scale but representative applications on quantum computers. The high-energy physics community plays a pivotal role in accessing the power of quantum computing, since the field is a driving source for challenging computational problems. This concerns, on the theoretical side, the exploration of models which are very hard or even impossible to address with classical techniques and, on the experimental side, the enormous data challenge of newly emerging experiments, such as the upgrade of the Large Hadron Collider. In this roadmap […]