Nathan’s Quantum Tech Newsletter: №1 — Space Quantum Communication
This is what I’ve seen in quantum tech this month, June 2017:
0 🛰 Focus: Space Quantum Communication
1 🗞 Tech News
10 🎓 Research Highlights
11 🎲 Bonus Links
0 🛰 Focus: Space Quantum Communication
A team of researchers based in China reported in Science on a milestone in quantum technologies research: the first quantum experiment initiated from a space satellite. Previous space experiments used existing satellites to mirror a signal sent from Earth back to Earth. This time the source of quantum correlation was on board of the satellite, which was launched in space with the specific purpose of performing this and future experiments. A laser-setup sent correlated photons to two cities in China, 1200 km apart. Analysis of the joint probability counts measuring the polarisation correlations revealed the violation of Bell’s inequalities, a test to discriminate between quantum mechanics and other theories of reality (roughly speaking). Link
Besides testing the nature of physical reality, quantum correlations can be used to encrypt information, a feature investigated by the field of research known as quantum communication. An end application would be new protocols for cybersecurity. While several countries and international collaborations are preparing to launch satellites for quantum experiments, China is certainly preeminent in the effort to establishing itself as the most advanced outpost for the implementation of quantum communication technology. Space is an integral part of that endeavour.
Chinese researchers plan to send to space other satellites to create a constellation within the next three years. Transmitting quantum information among different satellites allows to cover larger distances, as they occupy a part of space that is well over the lower (and thickest) part of the atmosphere, so that the signals can travel basically in vacuum, without suffering from absorption like on-ground open air transmission or optical fibre communication. It is worth to point out that the very characteristic that make quantum information secure, forbids it to be amplified with the schemes employed in conventional communication. Also for space a bottleneck still remains: when light was beamed down to the ground stations, out of millions of photons per second, only a fraction could be detected. Enough to accomplish this result.
The team lead by J.W. Pan has then uploaded a report on another quantum effect, teleportation. As detailed in the pre-print, available on a publicly accessible Internet archive, this experiment involved instead sending single photons from a ground station to the satellite. Link
1 🗞 Tech News
Rigetti, the quantum computing startup, has released Forest, a Python-based environment that will allow access from the cloud to the qubits of their machine. The California-based startup reported also the upgrade of its processors from one to eight qubits. Link
Rigetti’s advances arrive after earlier in March Google, and shortly after IBM, made announcements regarding their cloud-based projects. In a comment in the journal Nature researchers based at Google, together with an Europe-based venture capitalist, pointed out the need for an integrated academia-corporate approach to technology transfer and said they will offer access to their processors through cloud services to research players lacking “the necessary capital, expertise or infrastructure”. Link
Shortly after, IBM announced the rebranding of their decades-long research advances in the field under a new formal structure, IBM Q, and the opening of the beta-testing of their upgraded cloud-based quantum simulator. The IBM ‘Quantum Experience’ is already publicly accessible since 2016 and it has been succeeded in collecting the interest of a broad community of several thousands users, beyond that of quantum computation research experts. Even if changing from the current 5 qubits to 16 will have no immediate technological impact, it is relevant for academic researchers worldwide. Link
In the wake of all of this, a meeting on quantum computing hosted by a venture capital firm together with Google was held in Munich on June 22nd. Although many quantum-tech conferences now include industry sessions, this is probably the first meeting of this kind organised by a venture capital fund. Link
10 🎓 Research Highlights
Machine learning is applied to quantum physics (not yet the other way around). Subscription
While it is not possible to amplify signals with conventional methods, research on quantum repeaters is under way. Subscription
A long report on the state of the art in quantum chemistry, one of the killer application for quantum computing. Link
An important application of quantum computing to chemistry, from Microsoft Research and ETH Zurich (will require millions of qubits with low error rates). Link
Recent experiments test how quantum mechanics challenges the notion of causality. Comment
An experiment achieved the new record for how fast can entanglement be generated and shared between distant qubits, more than 7 thousands pairs per second (plots make a comparison with other experiments in the literature). Subscription
The main path pursued for commercial quantum computing is based on superconducting circuits, as implemented with different characteristics at IBM, Google, and Rigetti, among others. But there are also other approaches, explored both in academia and by private companies. In this context, a recent research article assessed the geometry of IBM’s publicly-accessible computer, based on a superconducting-qubit circuit, and that of an ion-based platform. The latter, the study shows, currently offers more connectivity, as each quantum bit can be interconnected with the others. The authors claim that the feature will bring advantages as the size of processors eventually scales up. The article is co-authored by Chris Monroe, who co-founded the only quantum computing venture based on trapped ions. Paywall
Terry Rudolph believes in yet another incarnation of quantum computing, which uses light particles both as carriers of information and for its manipulation. In particular, silicon-integrated optics will be able to leverage on the development achieved in the last decades by the current integrated-chip silicon industry facilities and production processes. While controlling single photons with optical gates remains one of the main challenges of this route, it is not a fundamental drawback, he claims. This approach is explored by at least one California-based stealth startup. Link
Research and technology transfer is taking different directions, each one with its advantages and drawbacks.
11 🎲 Bonus Links
A long-read by Philip Ball on how quantum mechanics is seen to trump common sense — does it really? Link
A personal research perspective on entanglement and quantum communication by Anton Zeilinger, one of the pioneers of the field. Link
Quantum thermodynamics full steam ahead. Link
Quantum skepticism: there is growing concern among part of the research community that the outcomes of the EU quantum-tech flagship initiative might be oversold. Link
This month’s newsletter is longer than future ones, as it included some information accumulated while beta-testing it. Feedback welcome.
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© Nathan Shammah — 2018 and beyond.
