Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: quantum physics

Molecular dynamics is at the point of simulating bulk matter – but don’t expect it to predict the future.

The TV series Devs took as its premise the idea that a quantum computer of sufficient power could simulate the world so completely that it could project events accurately back into the distant past (the Crucifixion or prehistory) and predict the future. At face value somewhat absurd, the scenario supplied a framework on which to hang questions about determinism and free will (and less happily, the Many Worlds interpretation of quantum mechanics).

Quite what quantum computers will do for molecular simulations remains to be seen, but the excitement about them shouldn’t eclipse the staggering advances still being made in classical simulation. Full ab initio quantum-chemical calculations are very computationally expensive even with the inevitable approximations they entail, so it has been challenging to bring this degree of precision to traditional molecular dynamics, where molecular interactions are still typically described by classical potentials. Even simulating pure water, where accurate modelling of hydrogen bonding and the ionic disassociation of molecules involves quantum effects, has been tough.

Read more | >

Fault-tolerant logic gates will consume a large proportion of the resources of a two-dimensional quantum computing architecture. Here we show how to perform a fault-tolerant non-Clifford gate with the surface code; a quantum error-correcting code now under intensive development. This alleviates the need for distillation or higher-dimensional components to complete a universal gate set. The operation uses both local transversal gates and code deformations over a time that scales with the size of the qubit array. An important component of the gate is a just-in-time decoder. These decoding algorithms allow us to draw upon the advantages of three-dimensional models using only a two-dimensional array of live qubits. Our gate is completed using parity checks of weight no greater than four. We therefore expect it to be amenable with near-future technology. As the gate circumvents the need for magic-state distillation, it may reduce the resource overhead of surface-code quantum computation considerably.

A scalable quantum computer is expected to solve difficult problems that are intractable with classical technology. Scaling such a machine to a useful size will necessarily require fault-tolerant components that protect quantum information as the data is processed (1–4). If we are to see the realization of a quantum computer, its design must respect the constraints of the quantum architecture that can be prepared in the laboratory. In many cases, for instance, superconducting qubits (5–7), this restricts us to two-dimensional architectures.

Leading candidate models for fault-tolerant quantum computation are based on the surface code (3, 8) due to its high threshold (9) and multitude of ways of performing Clifford gates (10). Universal quantum computation is possible if this gate set is supplemented by a non-Clifford gate. Among the most feasible approaches to realize a non-Clifford gate is by the use of magic-state distillation (11). However, this is somewhat prohibitive as a large fraction of the resources of a quantum computer will be expended by these protocols (12, 13).

Read more | >

Microsoft today announced that Azure Quantum, its partner-centric quantum computing platform for developers who want to get started with quantum computing, is now in limited preview. First announced at Microsoft Ignite 2019, Azure Quantum brings together the hardware from IonQ, Honeywell, QCI and Microsoft, services from the likes of 1QBit, and the classical computing capabilities of the Azure cloud. With this move to being in limited preview, Microsoft is now opening the service up to a small number of select partners and customers.

At its current stage, quantum computing isn’t exactly a mission-critical capability for any business, but given how fast things are moving and how powerful the technology will be once it’s matured a bit over the next few years, many experts argue that now is the time to get started — especially because of how different quantum computing is from classical computing and how it will take developers a while to develop.

Read more | >

Quantum technology is not a phrase discussed over kitchen tables in Australia, but perhaps it should be.

Australia’s quantum technology research has been breaking new ground for almost 30 years. Governments, universities and more recently multinationals have all invested in this research.

Quantum technology is set to transform electronics, communications, computation, sensing and other fields. In the process it can create new markets, new applications and new jobs in Australia.

Read more | >

Quantum computers theoretically can prove more powerful than any supercomputer, and now scientists calculate just what quantum computers need to attain such “quantum supremacy,” and whether or not Google achieved it with its claims last year.

Whereas classical computers switch transistors either on or off to symbolize data as ones or zeroes, quantum computers use quantum bits—qubits—that, because of the bizarre nature of quantum physics, can be in a state of superposition where they are both 1 and 0 simultaneously.

Superposition lets one qubit perform two calculations at once, and if two qubits are linked through a quantum effect known as entanglement, they can help perform 22 or four calculations simultaneously; three qubits, 23 or eight calculations; and so on. In principle, a quantum computer with 300 qubits could perform more calculations in an instant than there are atoms in the visible universe.

Read more | >

Error suppression opens pathway to universal quantum computing.

A scientist at the University of Sydney has achieved what one quantum industry insider has described as “something that many researchers thought was impossible.”

Dr. Benjamin Brown from the School of Physics has developed a type of error-correcting code for quantum computers that will free up more hardware to do useful calculations. It also provides an approach that will allow companies like Google and IBM to design better quantum microchips.

Read more | >

A team of quantum physicists from a UAE-based research lab has developed a rapid laser test to detect COVID-19 patients, which can reduce the testing time to a few seconds with an accuracy rate of 85–90 percent and has the potential to replace the current nasal swab and blood tests that take several hours to process.

QuantLase Imaging Lab, the medical research arm of the Abu Dhabi-based International Holdings Company, in a press statement said that the rapid test uses a novel equipment which enables for much faster mass screening, with test results available in seconds and allowing testing on a wider scale including in public places.

The test uses laser to detect changes in the blood that could identify carriers before they become contagious and will cost as low as 100 dirhams (193 yuan, 27 U.S. dollars), according to researchers involved with the project.

Read more | >

The development of next-generation solar power technology that has potential to be used as a flexible ‘skin’ over hard surfaces has moved a step closer, thanks to a significant breakthrough at The University of Queensland.

UQ researchers set a world record for the conversion of solar energy to electricity via the use of tiny nanoparticles called ‘quantum dots’, which pass electrons between one another and generate electrical current when exposed to solar energy in a solar cell device.

The development represents a significant step towards making the technology commercially-viable and supporting global renewable energy targets.

Read more | >

String theory provides a microscopic description of the entropy of certain theoretical black holes—an important step toward understanding black hole thermodynamics.

In the 1970’s, theorists determined that black holes have entropy [1], a remarkable finding that points at analogies between these spacetime singularities and systems of particles, such as classical gases. The crucial proof was provided by Stephen Hawking, who demonstrated, using a quantum-mechanical framework, that black holes radiate as if they were black bodies with a specific temperature [2]. The analogy was completed by extending all four laws of thermodynamics to black holes [3]. In thermodynamics, entropy is an important bridge between the macroscopic and the microscopic world: In a gas, for instance, entropy relates macroscopic heat transfer to the number of available microscopic states of the gas molecules. Providing a similar microscopic explanation of black hole entropy is an important test for theories that aim to unify gravity and quantum mechanics.

Read more | >