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It’s not yet clear whether a theory that unites general relativity and quantum mechanics would permit time travel.

A new paper from researchers at the University of Chicago introduces a technique for compiling highly optimized quantum instructions that can be executed on near-term hardware. This technique is particularly well suited to a new class of variational quantum algorithms, which are promising candidates for demonstrating useful quantum speedups. The new work was enabled by uniting ideas across the stack, spanning quantum algorithms, machine learning, compilers, and device physics. The interdisciplinary research was carried out by members of the EPiQC (Enabling Practical-scale Quantum Computation) collaboration, an NSF Expedition in Computing.

Adapting to a New Paradigm for Quantum Algorithms

The original vision for quantum algorithms dates to the early 1980s, when physicist Richard Feynman proposed performing molecular simulations using just thousands of noise-less qubits (quantum bits), a practically impossible task for traditional computers. Other algorithms developed in the 1990s and 2000s demonstrated that thousands of noise-less qubits would also offer dramatic speedups for problems such as database search, integer factoring, and matrix algebra. However, despite recent advances in quantum hardware, these algorithms are still decades away from scalable realizations, because current hardware features noisy qubits.

Researchers from Aalto University and VTT Technical Research Centre of Finland have built a super-sensitive bolometer, a type of thermal radiation detector. The new radiation detector, made of a gold-palladium mixture makes it easier to measure the strength of electromagnetic radiation in real time. Bolometers are used widely in thermal cameras in the construction industry and in satellites to measure cosmic radiation.

The new developments may help bolometers find their way to quantum computers. If the new radiation detector manages to function as well in space as it does in the laboratory, it can also be used to measure cosmic microwave background radiation in space more accurately.

“The new detector is extremely sensitive, and its noise level—how much the signal bounces around the correct value, is only one tenth of the noise of any other bolometer. It is also a hundred times faster than previous low-noise radiation detectors,” says Mikko Möttönen, who works as a joint Professor of Quantum Technology at Aalto University and VTT.

Researchers at EPFL have created a metallic microdevice in which they can define and tune patterns of superconductivity. Their discovery, which holds great promise for quantum technologies of the future, has just been published in Science.

In superconductors, electrons travel with no resistance. This phenomenon currently only occurs at very low temperatures. There are many practical applications, such as magnetic resonance imaging (MRI). Future technologies, however, will harness the total synchrony of electronic behavior in superconductors—a property called the phase. There is currently a race to build the world’s first quantum computer, which will use phases to perform calculations. Conventional superconductors are very robust and hard to influence, and the challenge is to find new materials in which the superconducting state can be easily manipulated in a device.

EPFL’s Laboratory of Quantum Materials (QMAT), headed by Philip Moll, has been working on a specific group of unconventional superconductors known as heavy fermion materials. The QMAT scientists, as part of a broad international collaboration between EPFL, the Max Planck Institute for Chemical Physics of Solids, the Los Alamos National Laboratory and Cornell University, made a surprising discovery about one of these materials, CeIrIn₅.

A team of Northwestern University researchers is the first to document the role chemistry will play in next generation computing and communication. By applying their expertise to the field of Quantum Information Science (QIS), they discovered how to move quantum information on the nanoscale through quantum teleportation—an emerging topic within the field of QIS. Their findings were published in the journal, Nature Chemistry, on September 23, 2019, and have untold potential to influence future research and application.

Quantum teleportation allows for the transfer of quantum information from one location to another, in addition to a more secure delivery of that information through significantly improved encryption.

The QIS field of research has long been the domain of physicists, and only in the past decade has drawn the attention and involvement of chemists who have applied their expertise to exploit the quantum nature of molecules for QIS applications.

This newly discovered superconducting material could be the building blocks for Quantum Computers.

Quantum computers with the ability to perform complex calculations, encrypt data more securely and more quickly predict the spread of viruses, may be within closer reach thanks to a new discovery by Johns Hopkins researchers.

“We’ve found that a certain superconducting material contains special properties that could be the building blocks for technology of the future,” says Yufan Li, a postdoctoral fellow in the Department of Physics & Astronomy at The Johns Hopkins University and the paper’s first author.

The findings will be published October 11 in Science.

Researchers led by Delft University of Technology personnel have made two steps in the conversion of quantum states between signals in the microwave and optical domains. This is of great interest for connecting future superconducting quantum computers into a global quantum network. This week they report on their findings in Nature Physics and in Physical Review Letters.

Conversion between signals in the microwave and optical domains is of great interest, particularly for connecting future superconducting quantum computers into a global quantum network. Many leading efforts in quantum technologies, including superconducting qubits and quantum dots, share quantum information through photons in the microwave regime. While this allows for an impressive degree of quantum control, it also limits the distance the information can realistically travel before being lost to a mere few centimeters.

At the same time, the field of optical quantum communication has already seen demonstrations over distance scales capable of providing real-world applications. By transmitting information in the optical telecom band, fiber-based quantum networks over tens or even hundreds of kilometers can be envisaged. “In order to connect several quantum computing nodes over large distances into a quantum internet, it is therefore vital to be able to convert quantum information from the microwave to the optical domain, and back,” says Prof. Simon Groeblacher of Delft University of Technology. “This will not only be extremely interesting for quantum applications, but also for highly efficient, low-noise conversion between classical optical and electrical signals.”

Scientists have observed a quantum vibration at normal room temperature for the first time, a phenomenon that usually requires ultra-cold, carefully calibrated conditions – bringing us another step closer to understanding the behaviour of quantum mechanics in common materials.

The team was able to spot a phonon, a quantum particle of vibration generated from high-frequency laser pulses, in a piece of diamond. These phonons are notoriously hard to detect, partly because of their sensitivity to heat.

What makes observing a phonon so important is that it shows a vibration acting as a single unit of energy (as described by quantum mechanics), as well as a wave (as described by classical physics). At room temperature in open air conditions, it brings quantum behaviour “closer to our daily life” in the words of the researchers.