January 5, 2019
Quantum Optical Networks Closer to Reality. University of Chicago and Northwestern University researchers have overcome challenges in controlling single-photon emissions, a pre-requisite for integration of a quantum emitter (photon emitting device) into optical networks.
January 1, 2019
Solving Coherence and Initialization Problems of Qubits with Hybrid Qubits. Researchers at Japan’s RIKEN Center for Emergent Matter Science have succeeded in creating a device – an architecture based on semiconductors – for quantum computing which solves two problems plaguing the furtherance of quantum computing. Speed is critical to developing quantum computers, “First, the device must be able to be initialized quickly. Initialization is the process of putting a qubit into a certain state, and if that cannot be done rapidly it slows down the device. Second, it must maintain coherence for a time long enough to make a measurement. Coherence refers to the entanglement between two quantum states.” A long-enough coherence of the entangled qubits is needed to make a measurement – a “read out.” The result of a quantum calculation depends on the coherent state.
The hybrid qubits are composed of a single-spin qubit called a Loss-DiVincenzo qubit; its coherence time is ample for read-outs. “The second type, called a singlet-triplet qubit, is quickly initialized and read out, but it quickly becomes decoherent.” Combining the two, types of qubits were combined within the device architecture (known as a controlled-phase gate).
This combination within the architecture developed by the RIEKN team “allowed spin states to be entangled between the qubits in a time fast enough to maintain the coherence, allowing the state of the single-spin qubit to be read out by the fast singlet-triplet qubit measurement.”
Further study will determine if the qubit hybridization coupled with the controlled-phase gate architecture will lend to quantum computer scalability.
“Spin-based quantum computers have the potential to tackle difficult mathematical problems that cannot be solved using ordinary computers, but many problems remain in making these machines scalable. Now, an international group of researchers led by the RIKEN Center for Emergent Matter Science have crafted a new architecture for quantum computing. By constructing a hybrid device made from two different types of qubit—the fundamental computing element of quantum computers—they have created a device that can be quickly initialized and read out, and that simultaneously maintains high control fidelity. Schematic of the device [above].” (Image cradit: RIKEN Center for Emergent Matter Science, Japan)
Exploiting Light and Sound for Quantum Computing. Photon-phonon Brillouin scattering, an optical phenomenon observed in bulk crystals, optical fibers, and silicon waveguide devices, is potentially a quantum information processing method . “Moreover, Brillouin scattering provides a bridge between light and sound and offers an attractive path to coherently connect the microwave and optical domains.” Researchers in the U.K. have made significant progress in the challenges of material and surface photon absorption, furthering study of the uses of photon-phonon Brillouin scattering in quantum information processing applications.
December 28, 2018
Jian-Wei Pan, China’s Father of Quantum. Jian-Wei Pan. The mastermind behind China’s quantum ambitions. Will his work develop into an information and technological revolution?
December 19, 2018
Rice University, Army Research Office, Office of Naval Research, Support Study Into Imperfections in Quantum Photon Production. Materials theorists at the Rice Lab reported that “by adding pre-arranged imperfections to atom-thick materials like molybdenum disulfide, [the atoms] become perfectly capable of emitting single photons in either left or right polarization on demand.” Much of the control is brought about with the application of magnetic fields. Effectively, a quantum bit is created with a photon, molybdenum disulfide, and magnetism. In the end, you have a desired polarization which is method to storing quantum information as a quantum bit (qubit); the life-blood of a quantum computer.
December 14, 2018
Photon Entanglement at Large Scale: Precursor to Quantum Computer Memory. Delft University of Technology and University of Vienna physicists have entangled photons in “large” mechanical resonators. Though the time-to-live is measured in scant microseconds, the team believes the method of entanglement could be the pre-cursor to a quantum computer’s memory nodes. The team is advancing their research to show larger scale, more complex quantum states within the resonators.
December 12, 2018
Scaling Up Qubits Via Spin and Silicon. Long spin coherence times of quantum bits (qubits) are needed to enable effective quantum computing. Researchers at the University of New South Wales have gained sufficient understanding to control spin-orbit couplings. In doing so, scalability and large-scale quantum computing is closer to reality. Precise alignment of electric fields in “an atomically engineered device[s]” permitted the researchers to achieve spin lifetimes measured in minutes. Add the benefit of the seemingly ubiquitous silicon and its tech uses, this newly researched and developed coupling of the spin with electric fields provides added qubit selectivity.
University of Arkansas & Topological Quantum Materials. U.S. DoE grants University of Arkansas $750,000 to study topological quantum materials. The materials could lead to advancements in fields of quantum information and spintronics. Spintronics is the use of electron “spin” to record and store data. Reference is found at U of A…
December 10, 2018
Rochester Institute of Technology to Host Quantum Computing Workshop. Ample contributions from RIT and workshop sponsors have negated a registration fee; this speaks volumes and shows how high interest in the “Photonics for Quantum”, or PfQ, workshop to be held January 23-25, 2019 at RIT, is.
The “purpose of the workshop is to explore how photonic devices may impact quantum applications.” More clearly, the workshop will explore the U.S. National Quantum Initiative Act, and the use of photonic quantum devices in computing, communications, sensing and other applications.
Colloidal Quantum Dots: Smaller is Blue. Bigger is Red. Quantum dot LEDs gain efficiency; provide improved range of applications from environmental monitoring to biomedicals. Quantum research and development has many tangents. It will be interesting to see what the quantum computing nexus from CQD research might be.
December 3, 2018
Quantum Post-selection Limited? The Quantum mechanical method known as ‘post-selection’ has come upon limits to the quantum operations which can be ordered using the method. Reference is found here…