Lifeboat Foundation

A joint China-Austria team has performed quantum key distribution between the quantum-science satellite Micius and multiple ground stations located in Xinglong (near Beijing), Nanshan (near Urumqi), and Graz (near Vienna). Such experiments demonstrate the secure satellite-to-ground exchange of cryptographic keys during the passage of the satellite Micius over a ground station. Using Micius as a trusted relay, a secret key was created between China and Europe at locations separated up to 7,600 km on the Earth.

Private and secure communications are fundamental for Internet use and e-commerce, and it is important to establish a secure network with global protection of data. Traditional public key cryptography usually relies on the computational intractability of certain mathematical functions. In contrast, quantum key distribution (QKD) uses individual light quanta (single photons) in quantum superposition states to guarantee unconditional security between distant parties. Previously, the quantum communication distance has been limited to a few hundred kilometers due to optical channel losses of fibers or terrestrial free space. A promising solution to this problem exploits satellite and space-based links, which can conveniently connect two remote points on the Earth with greatly reduced channel loss, as most of the photons’ propagation path is through empty space with negligible loss and decoherence.

A cross-disciplinary multi-institutional team of scientists from the Chinese Academy of Sciences, led by Professor Jian-Wei Pan, has spent more than 10 years developing a sophisticated satellite, Micius, dedicated to quantum science experiments, which was launched on August 2016 and orbits at an altitude of ~500 km. Five ground stations in China coordinate with the Micius satellite. These are located in Xinglong (near Beijing), Nanshan (near Urumqi), Delingha (37°22’44.43’‘N, 97°43’37.01” E), Lijiang (26°41’38.15’‘N, 100°1’45.55’‘E), and Ngari in Tibet (32°19’30.07’‘N, 80°1’34.18’‘E).

Continue reading “Real-world intercontinental quantum communications enabled by the Micius satellite” »

A method of securely communicating between multiple quantum devices has been developed by a UCL-led team of scientists, bringing forward the reality of a large-scale, un- hackable quantum network.

To date, communicating via quantum networks has only been possible between two devices of known provenance that have been built securely.

With the EU and UK committing €1 billion and £270 million respectively into funding quantum technology research, a race is on to develop the first truly secure, large-scale network between cities that works for any quantum device.

From afar, it looks like a steampunk chandelier. An intricate collection of tubes and wires that culminate in a small steel cylinder at the bottom. It is, in fact, one of the most sophisticated quantum computers ever built. The processor inside has 50 quantum bits, or qubits, that process tasks in a (potentially) revolutionary way. Normally, information is created and stored as a series of ones and zeroes. Qubits can represent both values at the same time (known as superposition), which means a quantum computer can theoretically test the two simultaneously. Add more qubits and this hard-to-believe computational power increases.

Last November, IBM unveiled the world’s first 50-qubit quantum computer. It lives in a laboratory, inside a giant white case, with pumps to keep it cool and some traditional computers to manage the tasks or algorithms being initiated. At CES this year, the company brought the innards — the wires and tubes required to send signals to the chip and keep the system cool — so reporters and attendees could better understand how it works. The biggest challenge, IBM Research Vice President Jeffrey Welser told me, is isolating the chip from unwanted “noise.” This includes electrical, magnetic and thermal noise — just the temperature of the room renders the whole machine useless.

Researchers at Princeton University have constructed silicon hardware that can control quantum behaviour between two electrons with extremely high precision.

The team constructed a two qubit gate that controls interactions between the electrons in a way that allows them to act as the qubits necessary for quantum computing. The demonstration of the gate is being seen as an early step in building a more complex quantum computing device from silicon.

The gate was constructed by layering aluminium wires onto a highly ordered silicon crystal. The wires deliver voltages that trap two single electrons, separated by an energy barrier, in a double quantum dot.

Continue reading “Two qubit silicon gate has been created” »

A new conception of quantum mechanics rests on the idea that parallel universes exist, and that they interact with our own to create weird and wonderful quantum phenomena.

Intelligent Machines

Intel’s new chips are more brain-like than ever.

The troubled chipmaker is looking to the future of computing.

Continue reading “Intel wants to move beyond today’s architecture, with brain-inspired and quantum chips” »

A team from Griffith’s Centre for Quantum Dynamics in Australia have demonstrated how to rigorously test if pairs of photons — particles of light — display Einstein’s “spooky action at a distance”, even under adverse conditions that mimic those outside the lab.

They demonstrated that the effect, also known as quantum nonlocality, can still be verified even when many of the photons are lost by absorption or scattering as they travel from source to destination through an optical fiber channel. The experimental study and techniques are published in the journal Science Advances.

Quantum nonlocality is important in the development of new global quantum information networks, which will have transmission security guaranteed by the laws of physics. These are the networks where powerful quantum computers can be linked.

We’re used to dealing with three physical dimensions and one extra dimension of time as we move through the Universe, but two teams of scientists have shown that a fourth spatial dimension could reach beyond the limits of up and down, left and right, and forwards and backwards.

As you might expect given this is bending the laws of physics, the experiments involved are partly theoretical and very complex, and touch on our old friend quantum mechanics.

Continue reading “Experiments Show The Effects of a Fourth Spatial Dimension” »

To the best of our knowledge, we humans can only experience this world in three spatial dimensions (plus one time dimension): up and down, left and right, and forward and backward. But in two physics labs, scientists have found a way to represent a fourth spatial dimension.

This isn’t a fourth dimension that you can disappear into or anything like that. Instead, two teams of physicists engineered special two-dimensional setups, one with ultra-cold atoms and another with light particles. Both cases demonstrated different but complementary outcomes that looked the same as something called the “quantum Hall effect” occurring in four dimensions. These experiments could have important implications to fundamental science, or even allow engineers to access higher-dimension physics in our lower-dimension world.

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