Phys.org November 22, 2024 Striving for higher gate fidelity is crucial not only for enhancing existing noisy intermediate-scale quantum devices, but also for unleashing the potential of fault-tolerant quantum computation through quantum error correction. Researchers in Japan proposed theoretical scheme, the double-transmon coupler (DTC), that aims to achieve both suppressed residual interaction and a fast high-fidelity two-qubit gate simultaneously, particularly for highly detuned qubits. The state-of-the-art fabrication techniques and a model-free pulse-optimization process would enable not only efficient fault-tolerant quantum computing with error correction but also effectively mitigate errors in current noisy intermediate-scale quantum devices. According to the researchers the […]
Tag Archives: Quantum computation
Toward a code-breaking quantum computer
MIT News August 23, 2024 Researchers at MIT made two improvements to Regev’s quantum factoring algorithm by addressing its space efficiency and its noise-tolerance. They improved the quantum space efficiency of Regev’s algorithm by constructing a quantum factoring circuit using O(n log n) qubits and O(n3/2log n) gates. achieving the best of Shor and Regev gates. Optimization was achieved by implementing efficient and reversible exponentiation with Fibonacci numbers in the exponent, rather than the usual powers of 2. This technique allowed them to perform quantum modular exponentiation that was efficient in both space and size without requiring significant precomputation, a […]
Pseudomagic quantum states: A path to quantum supremacy
Phys.org June 11, 2024 An international team of researchers (USA – Harvard University, MIT, University of Chicago, Germany) introduced “pseudomagic” ensembles of quantum states that are computationally indistinguishable from those with high nonstabilizerness. They demonstrated that pseudomagic neither follows from pseudoentanglement nor implies it. It offers fresh insights into the theory of quantum scrambling: it uncovers states that, even though they originated from nonscrambling unitaries, remain indistinguishable from scrambled states to any physical observer. Applications include new lower bounds on state synthesis problems, property testing protocols, and implications for quantum cryptography. According to the researchers only quantities measurable by a […]
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, […]