RSA Encryption is an essential safeguard for our online communications. It was also destined to fail even before the Internet made RSA necessary, thanks the work of Peter Shor, whose algorithm in 1994 proved quantum computers could actually be used to solve problems classical computers could not.
Noise and imperfections in a quantum system can result in the presence and propagation of errors through the system. A reliable quantum processor will need to be able to correct for these errors and error syndromes. Rosenblum et al. used higher quantum states of a superconducting-based quantum circuit to demonstrate a method for the fault-tolerant measurement of an error-correctable logical qubit. Such fault-tolerant measurements will allow more frequent interrogations of the state of the logical qubit, ultimately leading to the implementation of more quantum operations and more complex entangled quantum circuits.
Science, this issue p. 266
A critical component of any quantum error–correcting scheme is detection of errors by using an ancilla system. However, errors occurring in the ancilla can propagate onto the logical qubit, irreversibly corrupting the encoded information. We demonstrate a fault-tolerant error-detection scheme that suppresses spreading of ancilla errors by a factor of 5, while maintaining the assignment fidelity. The same method is used to prevent propagation of ancilla excitations, increasing the logical qubit dephasing time by an order of magnitude. Our approach is hardware-efficient, as it uses a single multilevel transmon ancilla and a cavity-encoded logical qubit, whose interaction is engineered in situ by using an off-resonant sideband drive. The results demonstrate that hardware-efficient approaches that exploit system-specific error models can yield advances toward fault-tolerant quantum computation.
Continue reading “Fault-tolerant detection of a quantum error” »
Atomic BECs were first achieved in 1995. Although it has become easier to realize atomic BECs since their discovery, they still require very low temperatures for operation. For most purposes, this is too expensive and impractical. Alternatively, negatively charged quatrons are quasi-particles composed of a hole and three electrons which form a stable BEC when coupled to light in triple quantum layer structures in semiconductor microcavities. This allows for both the greater experimental control found in quantum optics, and the benefits of matter wave systems, such as superconductivity and coherence. Moreover, due to the extremely small effective mass of the quasi-particles, quatrons can be used to achieve superconducting BECs at room temperature.
The Create the Future Design Contest was launched in 2002 by the publishers of NASA Tech Briefs magazine to help stimulate and reward engineering innovation. The annual event has attracted more than 8,000 product design ideas from engineers, entrepreneurs, and students worldwide.
Yale researchers have figured out how to catch and save Schrödinger’s famous cat, the symbol of quantum superposition and unpredictability, by anticipating its jumps and acting in real time to save it from proverbial doom. In the process, they overturn years of cornerstone dogma in quantum physics.
The discovery enables researchers to set up an early warning system for imminent jumps of artificial atoms containing quantum information. A study announcing the discovery appears in the June 3 online edition of the journal Nature.
Schrödinger’s cat is a well-known paradox used to illustrate the concept of superposition—the ability for two opposite states to exist simultaneously—and unpredictability in quantum physics. The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. The superposition theory of quantum physics suggests that until someone opens the box, the cat is both alive and dead, a superposition of states. Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either dead or alive.
Continue reading “Physicists can predict the jumps of Schrodinger’s cat (and finally save it)” »
D-Wave Systems today unveiled the roadmap for its 5,000-qubit quantum computer. Components of D-Wave’s next-generation quantum computing platform will come to market between now and mid-2020 via ongoing quantum processing unit (QPU) and cloud-delivered software updates. The complete system will be available through cloud access and for on-premise installation in mid-2020.
Binary digits (bits) are the basic units of information in classical computing while quantum bits (qubits) make up quantum computing. Bits are always in a state of 0 or 1, while qubits can be in a state of 0, 1, or a superposition of the two. Quantum computing leverages qubits to perform computations that would be much more difficult for a classical computer. Based in Burnaby, Canada, D-Wave has been developing its own quantum computers that use quantum annealing.
D-Wave is mainly focused on solving optimization problems, so its quantum computers can’t be directly compared to the competition. Indeed, many have questioned whether D-Wave’s systems have quantum properties, and thus performance that classical computers can’t match. In the meantime, D-Wave continues to improve and sell its systems.
Continue reading “D-Wave previews quantum computing platform with over 5,000 qubits” »
The techniques of microwave quantum optics are applied to collective spin excitations in a macroscopic sphere of ferromagnetic insulator. We demonstrate.
In the single-magnon limit, strong coupling between a magnetostatic mode in the sphere and a microwave cavity mode. Moreover, we introduce a superconducting qubit in the cavity and couple the qubit with the magnon excitation via the virtual photon excitation. We observe the magnon-vacuum-induced Rabi splitting.
The hybrid quantum system enables generation and characterization of non-classical quantum states of magnons.
