Phys.org February 2, 2023 An international team of researchers (UK, Italy) has reported the experimental realization of the prime number quantum potential VN(x), defined as the potential entering the single-particle Schrödinger Hamiltonian with eigenvalues given by the first N prime numbers. Using computer-generated holography, they created light intensity profiles suitable to optically trap ultracold atoms in these potentials for different N values. As a further application, they implemented a potential whose spectrum is given by the lucky numbers, a sequence of integers generated by a different sieve than the familiar Eratosthenes’s sieve used for the primes. According to the researchers their results pave the way […]
Tag Archives: Quantum computing
New quantum computing architecture could be used to connect large-scale devices
Science Daily January 5, 2023 Quantum information transfer between arbitrary nodes is generally mediated either by photons that propagate between them or by resonantly coupling nearby nodes. The utility is determined by the type of emitter, propagation channel and receiver. Conventional approaches involving propagating microwave photons have limited fidelity due to photon loss and are often unidirectional, whereas architectures that use direct resonant coupling are bidirectional in principle but can generally accommodate only a few local nodes. Researchers at MIT have demonstrated high-fidelity, on-demand, directional, microwave photon emission by using an artificial molecule comprising two superconducting qubits strongly coupled to […]
Imposter physical particles revealed: A key advance for quantum technology
Phys.org December 16, 2022 Hybrid semiconductor–superconductor devices hold great promise for realizing topological quantum computing with Majorana zero modes. However, multiple claims of Majorana detection, based on either tunnelling or Coulomb blockade (CB) spectroscopy, remain disputed. An international team of researchers (Austria, USA – Princeton University, Spain) devised an experimental protocol that allowed them to perform both types of measurement on the same hybrid island by adjusting its charging energy via tunable junctions to the normal leads. This method reduces ambiguities of Majorana detections by checking the consistency between CB spectroscopy and zero-bias peaks in non-blockaded transport. They observed junction-dependent, […]
Electron pairing in quantum dots as a new approach to qubit research
Phys.org November 25, 2022 Materials with intrinsic p-wave superconductivity, hosting Cooper pairs made of equal-spin electrons, have not been conclusively identified, nor synthesized, despite promising progress. Instead, engineered platforms where s-wave superconductors are brought into contact with magnetic materials have shown convincing signatures of equal-spin pairing. Researchers in the Netherlands have directly measured equal-spin pairing between spin-polarized quantum dots. The pairing is proximity-induced from an s-wave superconductor into a semiconducting nanowire with strong spin–orbit interaction. They demonstrated such pairing by showing that breaking a Cooper pair can result in two electrons with equal spin polarization. Their results demonstrated controllable detection […]
Erbium atoms in silicon: A prime candidate for quantum networks
Phys.org November 7, 2022 A major challenge for a scalable architecture for quantum information processing is based on emitters in nanostructures that are coupled by light. Researchers in Germany demonstrated the integration of erbium atoms with special optical properties into a silicon crystal. Thus, the atoms could be connected by light at a wavelength that is commonly used in telecommunications, making them ideal building blocks for future quantum networks that enable calculations with several quantum computers, as well as the secure exchange of data in a quantum internet. They achieved a narrow inhomogeneous broadening, less than 1 GHz, strong optical […]
From bits to p-bits: One step closer to probabilistic computing
Nanowerk August 29, 2022 To engineer probabilistic computers for more advanced computers researchers in Japan have developed a mathematical description to understand what happens to p-bits which could form the basis of probablistic computing. They utilized superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determined the exponents through several independent measurements. They experimentally clarified the ‘switching exponent’ that governs fluctuation under the perturbations caused by magnetic field and spin-transfer torque in magnetic tunnel junctions. This gave them the mathematical foundation to implement magnetic tunnel junctions into the p-bit to sophisticatedly design probabilistic computers. They showed that these […]
A Huge Step Forward in Quantum Computing Was Just Announced: The First-Ever Quantum Circuit
Science Alert June 22, 2022 Researchers in Australia have created a functional quantum processor and tested it by modeling a small molecule in which each atom has multiple quantum states. They used a scanning tunneling microscope in an ultra-high vacuum to place quantum dots with sub-nanometer precision. The trickiest parts were figuring out: exactly how many atoms of phosphorus should be in each quantum dot; exactly how far apart each dot should be; and then engineering a machine that could place the tiny dots in exactly the right arrangement inside the silicon chip. The final quantum chip contained 10 quantum […]
Developing the next generation of quantum algorithms and materials
Phys.org June 6, 2022 In its current stage of development, quantum computing is still very sensitive to noise and disruptive factors in the environment. To overcome these limitations a team of researchers in the US (Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory, Microsoft, MIT, MIT Lincoln Laboratory, Washington University) is developing simulations that provide a glimpse into how quantum computers work. They combined two different types of simulations to create the Northwest Quantum Simulator (NWQ-Sim) to test quantum algorithms. It can help us look beyond the limitations of the existing devices and test algorithms for more sophisticated systems. […]
Building a better quantum bit: New qubit breakthrough could transform quantum computing
Phys.org May 4, 2022 A team of researchers in the US (Argonne National Laboratory, Lawrence Berkeley National Laboratory, research organization, MIT, University of Chicago, National High Magnetic Field Laboratory, Florida State University, Washington University) trapped an electron on an ultrapure solid neon surface in a vacuum. After building their platform, the team performed real-time qubit operations using microwave photons on a trapped electron and characterized its quantum properties. These tests demonstrated that solid neon provided a robust environment for the electron with very low electric noise to disturb it. By using a chip-scale superconducting resonator the team was able to […]
Graphene spintronics: 1D contacts improve mobility in nano-scale devices
Science Daily February 11, 2022 An international team of researchers (UK, Japan) used monolayer graphene encapsulated by hexagonal boron nitride in van der Waals heterostructure with one-dimensional contacts. They measured electron mobility up to 130,000cm2/Vs at low temperatures (20K or -253oC) and spin diffusion lengths approaching 20 μm. The nanoscale-wide 1D contacts allow spin injection both at room and at low temperature, with the latter exhibiting efficiency comparable with 2D tunnel contacts. At low temperature, the spin signals can be enhanced by as much as an order of magnitude by electrostatic gating, adding new functionality. According to the researchers the […]