New materials and techniques show promise for microelectronics and quantum technologies

Phys.org  October 2, 2024 Low dimensional (LD) organic metal halide hybrids (OMHHs) have recently emerged as new generation functional materials with exceptional structural and property tunability. Despite the remarkable advances in the development of LD OMHHs, optical properties have been the major functionality extensively investigated for most of LD OMHHs developed to date, while other properties such as magnetic and electronic properties, remain significantly under-explored. An international team of researchers (USA – Florida State University, North Carolina State University, UCLA, Israel) describe the characterization of the magnetic and electronic properties of a 1D OMHH, organic-copper (II) chloride hybrid (C8H22N2)Cu2Cl6. Due […]

Proof-of-concept design shrinks quantum rotation sensor to micron scale

Phys.org  October 1, 2024 A team of researchers in the US (University of Michigan, DEVCOM Army Research Laboratory) investigated the possible realization of an ultracold-atom rotation sensor that was based on recently proposed tractor atom interferometry (TAI). They described an experimental design that included the generation of a Laguerre–Gaussian-beam-based “pinwheel” optical lattice and multi-loop interferometric cycles. Numerical simulations of the proposed system demonstrated TAI rotation sensitivity comparable to that of contemporary matter-wave interferometers. They applied quantum optimal control to devise a methodology suitable to address nonadiabaticity which might hinder systems performance. According to the researchers their studies are of interest […]

Significant new discovery in teleportation research — Noise can improve the quality of quantum teleportation

Science Daily  May 2, 2024 While quantum teleportation is fueled by a pair of maximally entangled resource qubits, it is vulnerable to decoherence. An international team of researchers (China, Finland) proposed an efficient quantum teleportation protocol in the presence of pure decoherence and without entangled resource qubits entering the Bell-state measurement. They used multipartite hybrid entanglement between the auxiliary qubits and their local environments within the open–quantum system context. With a hybrid-entangled initial state, it is the decoherence that allowed them to achieve high fidelities. They demonstrated their protocol in an all-optical experiment… read more. Open Access TECHNICAL ARTICLE

Combating disruptive ‘noise’ in quantum communication

Phys.org  April 15, 2024 Nonlocality is crucial for device-independent technologies like quantum key distribution and randomness generation. It quickly deteriorates in the presence of noise, and restoring nonlocal correlations requires additional resources incurring a significant resource overhead. An international team of researchers (Australia, France, USA – NIST, Boulder, CO) experimentally demonstrated that single copies of Bell-local states, incapable of violating any standard Bell inequality, could give rise to nonlocality after being embedded into a quantum network of multiple parties. They subjected the initial entangled state to a quantum channel that broadcast part of the state to two independent receivers and […]

Research team takes a fundamental step toward a functioning quantum internet

Phys.org  February 7, 2024 Quantum repeater networks require independent absorptive quantum memories capable of storing and retrieving indistinguishable photons to perform high-repetition entanglement swapping operations. An international team of researchers (USA – Stony Brook University, industry, Brookhaven National Laboratory, Italy) performed Hong-Ou-Mandel (HOM) interference between photonic polarization states and single-photon-level pulses stored and retrieved from two sets of independent room-temperature quantum memories. They showed that the storage and retrieval of polarization states from quantum memories did not degrade the HOM visibility for few-photon-level polarization states in a dual-rail configuration. For single-photon-level pulses, they measured the HOM visibility with various levels […]

Combining diamond and lithium niobate as a core component for future quantum technologies

Nanowerk  December 15, 2023 Negatively charged group-IV color centers in diamond are promising candidates for quantum memories as they combine long storage times with excellent optical emission properties and an optically addressable spin state. However, as a material, diamond lacks the many functionalities needed to realize scalable quantum systems. Thin-film lithium niobate (TFLN), in contrast, offers several useful photonic nonlinearities, including the electro-optic effect, piezoelectricity, and capabilities for periodically poled quasi-phase matching. Researchers at Stanford University have presented highly efficient heterogeneous integration of diamond nanobeams containing negatively charged silicon-vacancy (SiV) centers with TFLN waveguides. They observed greater than 90% transmission […]

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 […]

Scientists develop fermionic quantum processor

Phys.org  August 23, 2023 Although qubit-based quantum computers can potentially simulate the properties of many-body fermionic systems more efficiently than classical devices, encoding nonlocal fermionic statistics introduces an overhead in the required resources, limiting their applicability on near-term architectures. An international team of researchers (Austria, USA – Harvard University, University of Colorado) has demonstrated a fermionic quantum processor, where fermionic models were locally encoded in a fermionic register and simulated in a hardware-efficient manner using fermionic gates. They considered fermionic atoms in programmable tweezer arrays and developed different protocols to implement nonlocal gates, guaranteeing Fermi statistics at the hardware level. […]

Fluxonium Qubit Retains Information For 1.43 Milliseconds – 10x Longer Than Before

Science Alert  July 6, 2023 An international team of researchers (USA- University of Maryland, Switzerland) has built a fluxonium qubit that could retain information for 1.43 milliseconds. The superconducting fluxonium qubit had uncorrected coherence time T∗2=1.48±0.13ms, exceeding the state of the art for transmons by an order of magnitude. The average gate fidelity was benchmarked at 0.99991(1). Even in the millisecond range, the coherence time was limited by material absorption and could be further improved with a more rigorous fabrication. According to the researchers their demonstration may be useful for suppressing errors in the next generation quantum processors… read more. […]

New research on self-locking light sources presents opportunities for quantum technologies

Nanowerk  June 19, 2023 An international team of researchers (Argentina, Germany) demonstrated that light emitters with different resonance frequencies can asynchronously self-lock their relative energies by exchanging mechanical energy. They introduced polaromechanical metamaterials, two-dimensional arrays of μm-sized traps confining zero-dimensional light-matter polariton fluids and GHz phonons. A strong exciton-mediated polariton-phonon interaction induced a time-dependent inter-site polariton coupling J(t) with remarkable consequences for the dynamics. When locally perturbed by continuous wave optical excitation, a mechanical self-oscillation started and polaritons responded by locking the energy detuning between neighbor sites at integer multiples of the phonon energy showing asynchronous locking involving the polariton […]