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 […]

New cooling technology developed for quantum computing circuits

Phys.org  June 16, 2023 Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK – far above the refrigerator base temperature. This is reflected in the thermal state population of qubits and polarisation of surface spins. An international team of researchers (UK, Sweden, USA – industry) demonstrated how to remove this thermal constraint by operating a circuit immersed in liquid 3He. This allowed cooling tof he decohering environment of a superconducting resonator. They saw a continuous change in measured physical […]

New technique in error-prone quantum computing makes classical computers sweat

Phys.org  June 14, 2023 The widely accepted solution to noise in quantum computing is the implementation of fault-tolerant quantum circuits, which is out of reach for current processors. A team of researchers in the US (IBM -Yorktown Heights, NY, UC Berkeley) conducted experiments on a noisy 127-qubit processor and demonstrated the measurement of accurate expectation values for circuit volumes at a scale beyond brute-force classical computation. According to the researchers this represents evidence for the utility of quantum computing in a pre-fault-tolerant era. They established the accuracy of the measured expectation values by comparing them with the output of exactly […]

A new way for quantum computing systems to keep their cool

MIT News  February 21, 2023 To overcome errors in the qubits due to heat in quantum systems, researchers at MIT developed a wireless communication system that enables a quantum computer to send and receive data to and from electronics outside the refrigerator using high-speed terahertz waves. A transceiver chip, cryostat, placed inside the fridge sends and receives data from a terahertz wave source outside the cryostat using backscatter. An array of antennas on top of the chip, each of which is only about 200 micrometers in size, act as tiny mirrors. These mirrors can be “turned on” to reflect waves […]