Phys.org February 14, 2024 Nonsignaling boxes (NS) are theoretical resources defined by the principle of no-faster-than-light communication. They generalize quantum correlations and some of them are known to collapse communication complexity (CC). However, this collapse is strongly believed to be unachievable in nature. An international team of researchers (France, Canada) provided intuition on which theories are unrealistic. They found a better sufficient condition for a nonlocal box to collapse CC, thus extended the known collapsing region. In some slices of NS, they showed that this condition coincides with an area outside of an ellipse… read more. TECHNICAL ARTICLE Full […]
Tag Archives: Quantum entanglement
Research group detects a quantum entanglement wave for the first time using real-space measurements
Science Daily August 23, 2023 Quantum magnets provide a powerful platform to explore complex quantum many-body phenomena. One example is triplon excitations, exotic many-body modes emerging from propagating singlet-triplet transitions. Researchers in Finland engineered a minimal quantum magnet from organic molecules and demonstrated the emergence of dispersive triplon modes in one- and two-dimensional assemblies probed with scanning tunneling microscopy and spectroscopy. According to the researchers their results provide the first demonstration of dispersive triplon excitations from a real-space measurement… read more. TECHNICAL ARTICLE
Wiring up quantum circuits with light
Science Daily May 18, 2023 Quantum entanglement is a key resource in currently developed quantum technologies. Sharing this fragile property between superconducting microwave circuits and optical or atomic systems would enable new functionalities, but this has been hindered by an energy scale mismatch of >104 and the resulting mutually imposed loss and noise. Researchers in Austria created and verified entanglement between microwave and optical fields in a millikelvin environment. Using an optically pulsed superconducting electro-optical device, they showed entanglement between propagating microwave and optical fields in the continuous variable domain. According to the researchers their work not only paves the […]
Generation of color-tunable high-performance LG laser beams via Janus OPO
Phys.org April 24, 2023 Laguerre-Gaussian (LG) modes of light wave can carry the external torque of photons as they move through space. However, LG mode laser sources do not yet exist. An international team of researchers (China, USA – University of Arkansas) has experimentally demonstrated highly efficient, highly pure, broadly tunable, and topological-charge-controllable LG modes from a Janus optical parametric oscillator (OPO). They designed the Janus OPO featuring a two-faced cavity mode to guarantee an efficient evolution from a Gaussian-shaped fundamental pump mode to a desired LG parametric mode. The output LG mode had a tunable wavelength between 1.5 and […]
Generating photons for communication in a quantum computing system
Phys.org October 10, 2020 Realizing a fully connected network of quantum processors requires the ability to distribute quantum entanglement. For distant processing nodes, this can be achieved by generating, routing, and capturing spatially entangled itinerant photons. Researchers at MIT and MIT Lincoln Laboratory have demonstrated the deterministic generation of such photons using superconducting transmon qubits that are directly coupled to a waveguide. They generated two-photon N00N states and showed that the state and spatial entanglement of the emitted photons are tunable via the qubit frequencies. Using quadrature amplitude detection, they reconstructed the moments and correlations of the photonic modes and […]
Scientists Have Demonstrated Quantum Entanglement on a Tiny Satellite Orbiting Earth
Science Alert June 28, 2020 A CubeSat launched last year from the International Space Station was specially designed to shield the entangled photon source from the pressures and temperatures of a launch from Earth. An international team of researchers (Singapore, Turkey, Switzerland, Australia, UK) describes the experiment which is composed of a source of entangled photon pairs coupled to a detector module all controlled by an integrated electronics subsystem. A micro-controller on the experiment interfaces to the satellite’s on-board computer to receive commands and to return science data to ground control. It operates using as little power as possible. The […]
NIST team builds hybrid quantum system by entangling molecule with atom
Phys.org May 20, 2020 Building on the their 2017 demonstration of quantum control of a molecule, a team of researchers in the US (NIST, University of Colorado) successfully entangled two energy levels of a calcium atomic ion with two different pairs of rotational states of a calcium hydride molecular ion, which is a calcium ion bonded to a hydrogen atom. The molecular qubit had a transition frequency—the speed of cycling between two rotational states—of either low energy at 13.4 kilohertz (kHz, thousands of cycles per second) or high energy at 855 billion cycles per second (gigahertz or GHz). Molecules could […]
Quantum-entangled light from a vibrating membrane
Phys.org March 31, 2020 Optical quantum states propagate with ultralow attenuation and resilient to ubiquitous thermal noise. Mechanical systems are envisioned as versatile interfaces between photons and a variety of solid-state quantm information processing platforms. Researchers in Denmark generated entanglement between two propagating optical modes by coupling them to the same cryogenic mechanical system. The entanglement persisted at room temperature. They verified the inseparability of the bipartite state and fully characterized its logarithmic negativity by homodyne tomography. Combined with quantum interfaces between mechanical systems and solid-state qubit processors, this paves the way for mechanical systems enabling long-distance quantum information networking […]
Entangling photons generated millions of miles apart
Phys.org August 28, 2019 An international team of researchers (China, USA – Louisiana State University, Texas A&M University, Baylor University, Princeton University, Germany, UK) conducted an experiment to test quantum interference, entanglement, and nonlocality using two dissimilar photon sources, the Sun and a semiconductor quantum dot on the Earth, which are separated by approximately 150 million km. By making the photons indistinguishable in all degrees of freedom, they observed time-resolved two-photon quantum interference with a raw visibility of 0.796, well above the 0.5 classical limit, providing unambiguous evidence of the quantum nature of thermal light. Using the photons with no […]
Researchers create a ‘universal entangler’ for new quantum tech
Phys.org February 27, 2019 Using an entangling mechanism called an exponential-SWAP gate researchers at Yale University demonstrated the new technology by deterministically entangling encoded states in any chosen configuration or codes, each housed in two otherwise isolated, 3-D superconducting microwave cavities. The results provide a valuable building block for universal quantum computation using bosonic modes…read more. TECHNICAL ARTICLE