Phys.org October 16, 2024 Quantum metrology takes advantage of quantum correlations to enhance the sensitivity of sensors and measurement techniques beyond their fundamental classical limit. The use of both temporal and spatial correlations present in quantum states of light can extend quantum-enhanced sensing to a parallel configuration that can simultaneously probe an array of sensors or independently measure multiple parameters. Researchers at the University of Oklahoma used multispatial-mode bright twin beams of light to probe a four-sensor quadrant plasmonic array. They showed that it is possible to independently and simultaneously measure local changes in refractive index for all four sensors […]
Tag Archives: Quantum sensing
Physicists ease path to entanglement for quantum sensing
Phys.org August 26, 2024 Spin squeezing is a form of entanglement that reshapes the quantum projection noise to improve measurement precision. An international team of researchers (USA – Harvard University, UC Berkeley, Germany) provided numerical and analytic evidence for the following conjecture: any Hamiltonian exhibiting finite-temperature easy-plane ferromagnetism could be used to generate scalable spin squeezing, thereby enabling quantum-enhanced sensing. It is based on a connection between the quantum Fisher information of pure states and the spontaneous breaking of a continuous symmetry. They demonstrated that spin squeezing exhibits a phase diagram with a sharp transition between scalable squeezing and non-squeezing […]
Researchers develop general framework for designing quantum sensors
Phys.org July 30, 2024 Quantum systems of infinite dimension, such as bosonic oscillators, provide vast resources for quantum sensing. A general theory on how to manipulate such bosonic modes for sensing beyond parameter estimation is unknown. A team of researchers in the US (MIT, North Carolina State University) developed a general algorithmic framework, quantum signal processing interferometry (QSPI), for quantum sensing at the fundamental limits of quantum mechanics by generalizing Ramsey-type interferometry. The sensing protocol relied on performing nonlinear polynomial transformations on the oscillator’s quadrature operators by generalizing quantum signal processing (QSP) from qubits to hybrid qubit-oscillator systems. They used […]
A new record for atom-based quantum computers: 1,000 atomic qubits and rising
Phys.org February 15, 2024 Researchers in Germany designed a large-scale quantum-processing architecture surpassing the tier of 1000 atomic qubits. By tiling multiple microlens-generated tweezer arrays, each operated by an independent laser source, they eliminated laser-power limitations in the number of allocatable qubits. With two separate arrays, they implemented combined 2D configurations of 3000 qubit sites with a mean number of 1167(46) single-atom quantum systems. The transfer of atoms between the two arrays effectively. Supercharging one array designated as the quantum processing unit with atoms from the secondary array significantly increased the number of qubits and the initial filling fraction. They […]
Researchers demonstrate secure information transfer using spatial correlations in quantum entangled beams of light
Phys.org June 5, 2023 The ability to use the temporal and spatial degrees of freedom of quantum states of light to encode and transmit information is crucial for a robust and efficient quantum network. However, the potential offered by the large dimensionality of the spatial degree of freedom remains unfulfilled, as the necessary level of control required to encode information remains elusive. Researchers at the University of Oklahoma encoded information in the distribution of the spatial correlations of entangled twin beams by taking advantage of their dependence on the angular spectrum of the pump needed for four-wave mixing. They showed […]
Strange new phase of matter created in quantum computer acts like it has two time dimensions
Phys.org July 20, 2022 An international team of researchers (USA -research organization, UT Austin, UMass Amherst, Canada) has demonstrated an emergent dynamical symmetry-protected topological phase using an array of 10 trapped-ion of yitterbium as quantum processor. Each ion is individually held and controlled by electric fields produced by an ion trap and can be manipulated or measured using laser pulses. This phase showed edge qubits that are dynamically protected from control errors, crosstalk, and stray fields. The edge protection relies purely on emergent dynamical symmetries that are stable to generic coherent perturbations. The work paves the way for implementation of […]
Physicists build an atom laser that can stay on forever
Phys.org June 14, 2022 Bose–Einstein condensates (BECs) are important to quantum simulation and sensing. A long-standing constraint for quantum gas devices has been the need to execute cooling stages time-sequentially, restricting these devices to pulsed operation. Researchers in the Netherlands demonstrated continuous Bose–Einstein condensation by creating a continuous-wave (CW) condensate of strontium atoms that lasts indefinitely. The coherent matter wave is sustained by amplification through Bose-stimulated gain of atoms from a thermal bath. By steadily replenishing this bath while achieving 1,000 times higher phase-space densities than previous works they maintained the conditions for condensation. Their experiment is the matter wave […]
Novel quantum sensing possibilities with nonlinear optics of diamonds
Phys.org March 22, 2022 Taking advantage of the properties, especially the harmonic generation of nitrogen vacancy in diamond researchers Japan have presented an efficient and viable way for creating diamond-based nonlinear optical temperature sensing. Using infrared ultrashort pulse laser stimulation, the team found that the harmonic generation decreased with temperature over the range of 20–300°C. The temperature-dependent change was explained by mismatch due to the speed of different colors of light in the diamond. As the atomic lattice heats up, the difference in the index of refraction between the original light and the higher energy light created by harmonic generation […]
A new platform for customizable quantum devices
Phys.org February 24, 2022 A team of researchers in the US (MIT, Columbia University, University of Chicago, Northwestern University) focused on a group of molecules with a central chromium atom surrounded by four hydrocarbon molecules to demonstrate how a particular molecular family of qubits can be finely tuned over a broad spectrum. They used synthetic chemistry to modify the physics of the qubits. Using the ligand field strength, they demonstrated remarkable fine tuning and showed that the ligand field strengths are adjustable over a relatively broad spectrum, and that it also controls the molecule’s electronic properties. The light emitted by […]
Cooling radio waves to their quantum ground state
Phys.org October 15, 2021 In standard cryogenic systems thermal decoherence prevents access to the quantum regime for photon frequencies below the gigahertz domain. An international team of researchers (the Netherlands, Germany) engineered two superconducting LC circuits coupled by a photon-pressure interaction and demonstrated sideband cooling of a hot radio frequency (RF) circuit using a microwave cavity. Because of a substantially increased coupling strength, they obtained a large single-photon quantum cooperativity and reduced the thermal RF occupancy by 75% with less than one pump photon. For larger pump powers, the coupling rate exceeds the RF thermal decoherence rate by a factor […]