Nanowerk August 6, 2020 The previous work of an international team of researchers (Russia, USA – Argonne National Laboratory, University of Chicago) dealt with a predefined quantum state. The problem with having to know which state you are reversing is the need to record it. This was not really an issue for the small computer made up of two or three quantum bits, which was used in last year’s study. But scaling up the experiment ramps up the memory requirements. Each additional qubit doubles the amount of memory needed. To address this, the researchers came up with a universal algorithm […]
Tag Archives: Quantum science
New $25-million center to advance quantum science and engineering
EurekAlert July 21, 2020 A team of researchers (Harvard University, MIT, Stanford University, University of Delaware, University of Oregon, University of New Mexico, NIST, Los Alamos National Laboratory, MIT Lincoln Laboratory, Sandia National Laboratory) led by the Colorado University is launching a new quantum science and engineering research center under a grant from NSF. Quantum Systems through Entangled Science and Engineering (Q-SEnSE) will explore several “grand challenges” including quantum phenomena, such as quantum entanglement, will advance new frontiers in measurement science; how quantum sensing can help researchers to discover new fundamental physics; and how researchers can turn those advancements into […]
A Metal-like Quantum Gas: A pathbreaking platform for quantum simulation
EurekAlert June 22, 2020 Electronic properties of condensed matter are often determined by an intricate competition between kinetic energy that aims to overlap and delocalize electronic wave functions across the crystal lattice, and localizing electron-electron interactions. In contrast, the gaseous phase is characterized by valence electrons tightly localized around the ionic atom cores in discrete quantum states with well-defined energies. A hybrid state of matter is created when a gas of isolated atoms is suddenly excited to a state where electronic wave functions spatially overlap like in a solid. Researchers in Japan created such a hybrid state with overlapping high-lying electronic […]
Here’s a Blueprint for a Practical Quantum Computer
IEEE Spectrum March 24, 2020 Researchers in the Netherlands have found that the functions needed for a quantum computer can naturally be divided into five such groups, conceptually represented by five layers of control. They are: Application layer, a key part of the overall system; Directly below the application layer is the classical-processing layer, which has three basic functions; Underneath the classical layer are the digital-, analog-, and quantum-processing layers, which together make up a quantum processing unit (QPU). To prepare for these developments, chip designers, chip-fabrication-process engineers, cryogenic-control specialists, experts in mass data handling, quantum-algorithm developers, and others will […]
Towards an unhackable quantum internet
Eurekalert March 23, 2020 To send quantum signals across large distances without loss a team of researchers in the US (Harvard University, MIT) found a way to correct for signal loss with a prototype quantum node that can catch, store and entangle bits of quantum information by integrating an individual color-center into a nanofabricated diamond cavity, which confines the information-bearing photons and forces them to interact with the single color-center. They placed the device in a dilution refrigerator, which reaches temperatures close to absolute zero, and sent individual photons through fiber optic cables into the refrigerator, where they were efficiently […]
Qubits that operate at room temperature
Phys.org March 17, 2020 Defect-based quantum systems are often complicated by charge-state instabilities and interference by phonons, which can diminish spin-initialization fidelities and limit room-temperature operation. An international team of researchers (Hungary, Sweden, USA – Argonne National Laboratory, University of Chicago, IBM, Russia) identified a pathway around these drawbacks by showing that an engineered quantum well can stabilize the charge state of a qubit. They constructed a model for previously unattributed point defect centers in silicon carbide as a near-stacking fault axial divacancy and show how this model explains these defects’ robustness against photoionization and room temperature stability. These results […]
Engineers crack 58-year-old puzzle on way to quantum breakthrough
Phys.org March 11, 2020 Nuclear spins are featured in early proposals for solid-state quantum computers and demonstrations of quantum search and factoring algorithms. Scaling up such concepts requires controlling individual nuclei which can be detected when coupled to an electron An international team of researchers (Australia, USA – Sandia National Laboratory, Japan) has demonstrated the coherent quantum control of a single 123Sb (spin-7/2) nucleus using localized electric fields produced within a silicon nanoelectronic device. The method exploits an idea proposed in 1961 but not previously realized experimentally with a single nucleus. Their results are quantitatively supported by a microscopic theoretical […]
How a new quantum approach can develop faster algorithms to deduce complex networks
EurekAlert March 3, 2020 Complex networks form the basis of various applications in virtually all fields of science. To analyze and manipulate these networks, specific “search” algorithms are required. But conventional search algorithms are slow and, when dealing with large networks, require a long computational time. To develop more efficient quantum algorithms researchers in Japan performed numerical simulations on some basic fractal lattices to try to find out the relationship between the number of vertices and the optimal computational time in a quantum walk search. They confirmed that the scaling law for some fractal lattices varied according to their spectral […]
Quantum researchers able to split one photon into three
Phys.org February 27, 2020 By splitting one “pump photon” into two daughter photons, SPDC has had a crucial role in fundamental tests of quantum theory as well as many applications in quantum information processing. An international team of researchers (Canada, Spain, Sweden) used a flux-pumped, superconducting parametric resonator to split one microwave photon into three daughter photons. The triplet source is bright, producing a propagating photon flux comparable to ordinary two-photon SPDC. They clearly saw strong three-photon correlations in the output photons, even in the absence of normal two-photon correlations. The symmetry properties of these correlations allowed them to “fingerprint” […]
Structured light promises path to faster, more secure communications
Science Daily October 29, 2019 Researchers in South Africa review the recent progress in the emergence of a second quantum revolution ushering in control of quantum states, outlining the core concepts in a tutorial manner before delving into the advances made in creation, manipulation, and detection of such quantum states. They cover advances in using orbital angular momentum as well as vectoral states that are hybrid entangled, combining spatial modes with polarization to form an infinite set of two-dimensional spaces: multidimensional entanglement. The authors highlight the work in pushing the boundaries in both the dimension and the photon number, before […]