Phys.org September 29, 2023 An international team of researchers (Japan, Germany) has reported the observation and control of ultrafast many-body dynamics of electrons in ultracold Rydberg-excited atoms, spatially ordered in a three-dimensional Mott insulator (MI) with unity filling in an optical lattice. By mapping out the time-domain Ramsey interferometry in the picosecond timescale, they could deduce entanglement growth indicating the emergence of many-body correlations via dipolar forces. They analyzed the observations with different theoretical approaches and found that the semiclassical model broke down, indicating that quantum fluctuations play a decisive role in the observed dynamics. Combining picosecond Rydberg excitation with […]
Category Archives: Quantum entanglement
Researchers develop a light source that produces two entangled light beams
Phys.org January 3, 2023 In quantum entanglement when the systems interact with their surroundings, they almost immediately become disentangled. An international team of researchers (Brazil, USA – University of Oklahoma) produced a light source that produced two entangled light beams. The twin beams generated with a doubly resonant optical parameter oscillator (OPO) based on four-wave mixing in hot 85Rb vapor above threshold. They reconstructed the covariance matrix for several configurations and based on a full picture of the four-side band mode state, they studied entanglement between all possible bipartitions. They showed a robust generation of entanglement with stronger generation for […]
Quantum Entanglement Has Now Been Directly Observed at The Macroscopic Scale
Science Alert October 16, 2022 To date, entanglement has generally been limited to microscopic quantum units such as pairs or multiples of single ions, atoms, photons, and so on. Previous studies had also reported on macroscopic quantum entanglement, all the necessary measurements were recorded rather than inferred, and the entanglement was generated in a deterministic, non-random way. An international team of researchers (Finland, Australia) have shown how it’s possible to measure the position and momentum of the two drumheads at the same time, getting around Heisenberg’s Uncertainty Principle working with macroscopic drums (oscillators) in a state of quantum entanglement. In […]
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 […]
It takes three to tangle: Long-range quantum entanglement needs three-way interaction
Science Daily 6, 2022 Researchers in Japan provide simple theorems that show what kinds of long-range entanglement can survive at nonzero temperatures. At temperatures above absolute zero, quantum entanglement must contend with thermal jostling of particles, which is detrimental to long-range entanglement persisting at sufficiently high temperatures. Unlike high-temperature phases, however, there are relatively low temperatures in which not all long-range quantum effects are strictly prohibited, and long-range entanglement can survive even at room temperatures. They proved that entanglement between two subsystems has a finite characteristic length scale at arbitrary temperatures regardless of the system details and the spatial dimension. […]
Key witness helps scientists detect ‘spooky’ quantum entanglement in solid materials
Phys.org November 8, 2021 The lack of methods to experimentally detect and quantify entanglement in quantum matter impedes our ability to identify materials hosting highly entangled phases, such as quantum spin liquids. An international team of researchers (USA – Oak Ridge National Laboratory, Drew School, Germany, UK, France, Poland) tested three entanglement witnesses using a combination of neutron scattering experiments and computational simulations. Entanglement witnesses are techniques that act as data analysis tools to determine which spins cross the threshold between the classical and quantum realms. To ensure that the witnesses could be trusted, the team applied all three of them […]
A two-qubit engine powered by entanglement and local measurements
Phys.org April 26, 2021 As an immediate consequence of the effect of quantum mechanics, the measuring device provides both energy and entropy to the quantum system. Previously an international team of researchers (France, USA – University of Rochester, Washington University, Chapman University) introduced the proof of concept for a measurement-fueled engine based on a single qubit. Now they have introduced a two-qubit engine that is powered by entanglement and local measurements. Energy is extracted from the detuned qubits coherently exchanging a single excitation. Generalizing to an N-qubit chain, they showed that the low energy of the first qubit can be […]
Using drones to create local quantum networks
Phys.org January 18, 2021 Researchers in China built a small laser-generating device and affixed it to one of the drones. As it fired, photons were split in two, creating entangled pairs. One of the paired photons was directed toward another drone while the other was directed to a ground station. The drone that received the entangled photon served only as a relay—after refocusing, the photon was forwarded to a third drone, which then sent it to a second ground station. Motorized devices were used on the drones to ensure transmitters and received lined up properly for transmission of the entangled […]
When light and atoms share a common vibe
Phy.org December 18, 2020 An international team of researchers (Switzerland, USA- MIT) entangled the photon and the phonon produced in the fission of an incoming laser photon inside the crystal by designing an experiment in which the photon-phonon pair could be created at two different instants. Classically, it would result in a situation where the pair is created at time t1 with 50% probability, or later t2 with 50% probability. They measured the decay of these hybrid photon-phonon Bell correlations with sub-picosecond time resolution and found that they survive over several hundred oscillations at ambient conditions. Their method offers a […]
Quantum entanglement realized between distant large objects
Phys.org September 28, 2020 The disparity of hybrid systems and the vulnerability of quantum correlations have thus far hampered the generation of macroscopic hybrid entanglement. An international team of researchers (Spain, USA – University of Chicago, Denmark) generated an entangled state between the motion of a macroscopic mechanical oscillator and a collective atomic spin oscillator, as witnessed by an Einstein–Podolsky–Rosen variance below the separability limit, 0.83 ± 0.02 < 1. The mechanical oscillator is a millimetre-size dielectric membrane, and the spin oscillator is an ensemble of 109 atoms in a magnetic field. Light propagating through the two spatially separated systems […]