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 […]
Tag Archives: Quantum technology
Researchers release roadmap for the development of quantum information technologies
Phys.org December 14, 2022 Q-NEXT, a U.S. Department of Energy (DOE) National Quantum Information Science Research Center, has created a roadmap for quantum interconnects research and its impact for quantum information science and technology. Q-NEXT members and participants are from academia, industry, and DOE national laboratories. The roadmap addresses the role of quantum interconnects in three emerging areas of quantum information: computing, communication, and sensing. The roadmap reviews the materials, components and systems used for these purposes; summarizes relevant scientific questions and issues; and addresses the most pressing research needs. It distills these considerations into recommendations for strategic science and […]
A scalable quantum memory with a lifetime over 2 seconds and integrated error detection
Phys.org November 28, 2022 Because of their long coherence times and efficient optical interface, color centers in diamond are promising candidates for quantum memory nodes. Researchers at Harvard University integrated two-qubit network node based on silicon-vacancy centers (SiVs) in diamond nanophotonic cavities. The qubit register consisted of the SiV electron spin acting as a communication qubit and the strongly coupled silicon-29 nuclear spin acting as a memory qubit with a quantum memory time exceeding 2 seconds. They demonstrated electron-photon entangling gates at temperatures up to 1.5 kelvin and nucleus-photon entangling gates up to 4.3 kelvin and efficient error detection in […]
Quantum technology reaches unprecedented control over captured light
Phys.org September 27, 2022 An international team of researchers (Sweden, Japan) has developed a technique to overcome to noise and interference in quantum systems. Their technique could create any of the previously demonstrated states and the cubic phase state. They used a sequence of interleaved selective number-dependent arbitrary phase (SNAP) gates and displacements. The state preparation was optimized in two steps – first they used a gradient-descent algorithm to optimize the parameters of the SNAP and displacement gates; then optimized the envelope of the pulses implementing the SNAP gates. The results showed that this way of creating highly nonclassical states […]
Coupling of electron-hole pairs
Nanowerk September 5, 2022 In two-layered molybdenum disulfide, excitation with light produces two different types of electron-hole pairs: intralayer pairs, in which the electron and hole are localized in the same layer of the material, and interlayer pairs, whose hole and electron are in different layers and are therefore spatially separate from one another. The intralayer pairs interact strongly with light. The interlayer excitons are much dimmer but can be shifted to different energies and therefore allow researchers to adjust the absorbed wavelength. They exhibit very strong, nonlinear interactions with one another which play an essential role in many of […]
Why ‘erasure’ could be key to practical quantum computing
Phys.org September 1, 2022 The fundamental challenge to quantum computers is that the operations are noisy. Rather than focusing solely on reducing the number of errors a team of researchers in the US (Yale University, University of Wisconsin-Madison, Princeton) made errors more visible. They delved deeply into the actual physical causes of error and engineered their system so that the most common source of error effectively eliminates, rather than simply corrupting, the damaged data leading to “erasure error,” which is fundamentally easier to weed out than data that is corrupted but still looks like all the other data. Erasure errors […]
A quantum pump without a crank
Phys.org August 22, 2022 The pumping process can have topological origins, when considering the motion of quantum particles in spatially and temporally periodic potentials. However, the periodic evolution that drives these pumps has always been assumed to be imparted from outside. Researchers in Switzerland found an emergent mechanism for pumping in a quantum gas coupled to an optical resonator, where they observed a particle current without applying a periodic drive. The pumping potential experienced by the atoms is formed by the self-consistent cavity field interfering with the static laser field driving the atoms. The cavity field evolves between its two […]
A roadmap for the future of quantum simulation
Phys.org July 29, 2022 Many of the most promising short-term applications of quantum computers fall under the umbrella of quantum simulation: modelling the quantum properties of microscopic particles that are directly relevant to modern materials science, high-energy physics, and quantum chemistry. This would impact several important real-world applications, such as developing materials for batteries, industrial catalysis or nitrogen fixing. Quantum simulation can be performed not only on future fault-tolerant digital quantum computers but also through special-purpose analogue quantum simulators. An international team of researchers (UK, Germany, Austria, USA – industry) has provided an overview of the state of the art […]
Scientists invent ‘quantum flute’ that can make particles of light move together
Nanowerk July 7, 2022 Because of the combination of long coherence times and large interaction strengths, one of the leading experimental platforms for cavity QED involves coupling a superconducting circuit to a 3D microwave cavity. In this work. An international team of researchers (USA – University of Chicago, University Rutgers, University of Chicago, UC Berkeley, South Korea) demonstrated a variety of protocols for universal single-mode quantum control applicable across all cavity modes, using only a single drive line. They achieved this by developing a straightforward flute method for creating monolithic superconducting microwave cavities that reduces loss while simultaneously allowing control […]
Quantum network nodes with warm atoms
Science Daily June 24, 2022 An international team of researchers (Switzerland, Germany) built and successfully interfaced a single-photon source based on cavity-enhanced spontaneous parametric down-conversion in periodically poled potassium titanyl phosphate and a matched memory based on electromagnetically induced transparency in warm 87Rb vapor. The bandwidth of the photons emitted by the source was 370MHz, which is within the accepted bandwidth of the memory. The experimental complexity was kept low, with all components operating at or above room temperature. Read-out noise of the memory was considerably reduced by exploiting polarization selection rules in the hyperfine structure of spin-polarized atoms. They […]