MIT News May 29, 2024 Colour centres in diamond have emerged as a leading solid-state platform for advancing quantum technologies and recently achieved quantum advantage in secret key distribution. Blueprint studies indicate that general-purpose quantum computing using local quantum communication networks will require millions of physical qubits to encode thousands of logical qubits, presenting an open scalability challenge. An international team of researchers (MIT, DEVCOM, Army Research Laboratory, The MITRE Corporation, Cornell University, the Netherlands, Germany) introduced a modular quantum system-on-chip (QSoC) architecture that integrated thousands of individually addressable tin-vacancy spin qubits in two-dimensional arrays of quantum microchiplets into an […]
Category Archives: Quantum computers
Researchers develop compiler acceleration technology for quantum computers
Phys.org May 9, 2024 Researchers in Japan used a random search technique to find quantum gate sequences that implement perfect quantum state preparation or unitary operator synthesis with arbitrary targets. The approach was based on the recent discovery that there is a large multiplicity of quantum circuits that achieved unit fidelity in performing a given target operation, even at the minimum number of single-qubit and two-qubit gates needed to achieve unit fidelity. They showed that the fraction of perfect-fidelity quantum circuits increased rapidly as soon as the circuit size exceeded the minimum circuit size required for achieving unit fidelity. This […]
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 […]
Discovery may enable network interface for quantum computers
Phys.org October 5, 2023 The coupling of microwave and optical systems presents a challenge due to the natural incompatibility of energies, but potential applications range from optical interconnects for quantum computers to next-generation quantum microwave sensors, detectors, and coherent imagers. Emerging platforms are constrained by specific conditions. An international team of researchers (Poland, Denmark) designed a set-up using Rydberg atoms that allows wideband coupling of optical and microwave photons at room temperature. They demonstrated continuous-wave conversion of a 13.9 GHz field to a near-infrared optical signal using an ensemble of Rydberg atoms via a free-space six-wave mixing process designed to minimize […]
How splitting sound might lead to a new kind of quantum computer
Phys.org July 5, 2023 Linear optical quantum computing provides a desirable approach to quantum computing, with only a short list of required computational elements. The similarity between photons and phonons points to the interesting potential for linear mechanical quantum computing using phonons in place of photons. Although single-phonon sources and detectors have been demonstrated, a phononic beam splitter element remains an outstanding requirement. Researchers at the University of Chicago demonstrated such an element, using two superconducting qubits to fully characterize a beam splitter with single phonons. They used the beam splitter to demonstrate two-phonon interference, a requirement for two-qubit gates […]
Microsoft claims to have achieved first milestone in creating a reliable and practical quantum computer
Phys.org. June 24, 2023 Researchers at Microsoft (USA) engineered a new way to represent a logical qubit with hardware stability. They reported that the device could induce a phase of matter characterized by Majorana zero modes, such devices have demonstrated low enough disorder to pass the topological gap protocol, proving the technology is viable. They stated that it has created a new measure to gauge the performance of a quantum supercomputer: reliable quantum operations per second (rope), a figure that describes how many reliable operations a computer can execute in a single second. They suggest that for a machine to […]
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 […]
Absolute zero in the quantum computer: Formulation for the third law of thermodynamics
Phys.org April 4, 2023 Nernst’s unattainability principle states that infinite resources are required to cool a system to absolute zero temperature. An international team of researchers (Japan, Austria, Sweden, France, Denmark, Switzerland, Ireland, Brazil, Germany) provided a framework for identifying the resources that enable the creation of pure quantum states. They showed that perfect cooling is possible with Landauer energy cost given infinite time or control complexity. However, optimal protocols required complex unitaries generated by an external work source. Restricting to unitaries that can be run solely via a heat engine, they derived a novel Carnot-Landauer limit, along with protocols […]
Electrons zip along quantum highways in new material
Nanowerk November 9, 2022 An international team of researchers (USA – University of Chicago, Pennsylvania State University, Israel) discovered a new material, MnBi6Te10, which could be used to create quantum highways useful in connecting the internal components of energy-efficient quantum computers. In the ferromagnetic phase, an energy gap of 15 meV was resolved at the Dirac point on the MnBi2Te4 termination. In contrast, antiferromagnetic MnBi6Te10 exhibited gapless topological surface states on all terminations. Measurements revealed substantial Mn vacancies and Mn migration in ferromagnetic MnBi6Te10. They provided a conceptual framework where a cooperative interplay of these defects drove a delicate change […]
Unimon – A new qubit to boost quantum computers for useful applications
Nanowerk November 15, 2022 Superconducting qubits seem promising for useful quantum computers, but the currently wide-spread qubit designs and techniques do not yet provide high enough performance. Researchers in Finland have developed a superconducting-qubit type, the unimon, which combines the desired properties of increased anharmonicity, full insensitivity to dc charge noise, reduced sensitivity to flux noise, and a simple structure consisting only of a single Josephson junction in a resonator. In agreement with their quantum models, they measured the qubit frequency and increased anharmonicity at the optimal operation point. It yielded, 99.9% and 99.8% fidelity for 13 ns single-qubit gates on […]