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 […]

A blueprint for a quantum computer in reverse gear

Phys.org  May 4, 2023 If two integers are entered as the input value, the computer circuit returns their product. Researchers in Austria developed inversion of algorithms with the help of quantum computers. The logic of the circuit was encoded within ground states of a quantum system. Both multiplication and factorization could be understood as ground-state problems and solved using quantum optimization methods. The core of their work was the encoding of the basic building blocks of the multiplier circuit, specifically AND gates, half, and full adders with the parity architecture as the ground state problem on an ensemble of interacting […]

A quantum leap in computational performance of quantum processors

Phys.org  April 24, 2023 An international team of researchers (Israel, Germany, UAE) is improving the performance of superconducting qubits, the basic computation units of a superconducting quantum processor. They studied a series of tunable flux qubits inductively coupled to a coplanar waveguide resonator fabricated on a sapphire substrate. Each qubit included an asymmetric superconducting quantum interference device, which is controlled by the application of an external magnetic field and acts as a tunable Josephson junction. The tunability of the qubits is typically ±3.5GHz around their central gap frequency. The measured relaxation times are limited by dielectric losses in the substrate […]

New experiment translates quantum information between technologies in an important step for the quantum internet

Phys.org  March 24, 2023 Whereas ultracold atoms and superconducting circuits have since taken independent paths in the exploration of new physics, taking advantage of their complementary strengths in an integrated system enables access to fundamentally new parameter regimes and device capabilities. Taking advantage of their complementary strengths in an integrated system a team of researchers in the US (University of Chicago, Stanford University) developed a system, coupling an ensemble of cold 85Rb atoms simultaneously to an optically accessible, three-dimensional superconducting resonator and a vibration-suppressed optical cavity in a cryogenic (5 K) environment. To demonstrate the capabilities of the platform, they leveraged […]

Physicists entangle more than a dozen photons efficiently

Phys.org  August 25, 2022 Optical photons represent ideal qubit carriers. However, the most successful technique so far for creating photonic entanglement is inherently probabilistic and, therefore, subject to severe scalability limitations. Researchers in Germany generated up to 14 entangled photons in a defined way and with high efficiency by using a single atom to emit the photons and interweave them in a very specific way, they placed a rubidium atom at the center of an optical cavity and triggered the emission of a photon that is entangled with the quantum state of the atom. By repeating the process several times […]

Two teams use neutral atoms to create quantum circuits

Phys.org   April 22, 2022 Gate-model quantum computers promise to solve currently intractable computational problems if they can be operated at scale with long coherence times and high-fidelity logic. Neutral-atom hyperfine qubits provide inherent scalability owing to their identical characteristics, long coherence times and ability to be trapped in dense, multidimensional arrays. Combined with the strong entangling interactions provided by Rydberg states all the necessary characteristics for quantum computation are available. An international team of researchers (USA – University of Central Florida,  Harvard University, University of Wisconsin-Madison, industry, MIT, UK, Austria,) demonstrated several quantum algorithms on a programmable gate-model neutral-atom quantum […]

Running quantum software on a classical computer

EurekAlert  August 3, 2021 A key open question in quantum computing is whether quantum algorithms can potentially offer a significant advantage over classical algorithms for tasks of practical interest. An international team of researchers (USA – Flatiron Institute, Columbia University, Switzerland) has introduced a method to simulate layered quantum circuits consisting of parametrized gates suitable for near-term quantum computers. They used a neural-network parametrization of the many-qubit wavefunction focusing on states relevant for the Quantum Approximate Optimization Algorithm (QAOA). For the largest circuits simulated, they reached 54 qubits at 4 QAOA layers without requiring large-scale computational resources. For larger systems, […]

Rare open-access quantum computer now operational

EurekAlert  March 15, 2021 Scientists worldwide can use ion-based testbed at Sandia National Laboratories QSCOUT for research that might not be possible at their home institutions, without the cost or restrictions of using a commercial testbed. QSCOUT serves a need in the quantum community by gives users an uncommon amount of control over their research, opportunity to study the machine itself, which are not yet available in commercial quantum computing systems. It also saves theorists and scientists from the trouble of building their own machines. Sandia hopes to gain new insights into quantum performance and architecture as well as solve […]

Quantum effects help minimize communication flaws

EurekAlert  February 10, 2021 Both quantum computation and quantum communication are strongly deteriorated because quantum superposition state can be destroyed, or entanglement between two or more quantum particles can be lost. An international team of researchers (Austria, UK, Hong Kong, Switzerland, France, Canada) experimentally and numerically compare different ways in which two trajectories through a pair of noisy channels can be superposed. They observed that, within the framework of quantum interferometry, the use of channels in series with quantum-controlled operations generally yields the largest advantages. The results contribute to clarify the nature of these advantages in experimental quantum-optical scenarios and […]

Quantum systems learn joint computing

Phy.org  February 5, 2021 The big challenge in quantum computing is to realize scalable multi-qubit systems with cross-talk–free addressability and efficient coupling of arbitrarily selected qubits. Quantum networks promise a solution by integrating smaller qubit modules to a larger computing cluster. Such a distributed architecture, however, requires the capability to execute quantum-logic gates between distant qubits. An international team of researchers (Germany, Spain) experimentally realized such a gate over 60 meters. They employed an ancillary photon that they successively reflected from two remote qubit modules, followed by a heralding photon detection, which triggers a final qubit rotation. They used the […]