### Crucial connection for 'quantum internet' made for the first time

Researchers have produced, stored, and retrieved quantum information for the first time, a critical step in quantum networking.

Related topics:
quantum computing
· quantum state
· quantum mechanics
· physical review letters
· atoms

Researchers have produced, stored, and retrieved quantum information for the first time, a critical step in quantum networking.

Quantum Physics

Apr 16, 2024

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It's Saturday, which means that in a universe where the arrow of time moves backward, people have to go to work tomorrow. In such a hypothetical universe, Garfield hates Fridays—tough to imagine. This week, we looked at ...

If you were to throw a message in a bottle into a black hole, all of the information in it, down to the quantum level, would become completely scrambled. Because in black holes this scrambling happens as quickly and thoroughly ...

Analytical Chemistry

Apr 5, 2024

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Diving deep into quantum biology or cognitive science alone is challenging enough. That being said, a research team recently wrote a review article highlighting molecular quantum computing, a newly emerged research area that ...

Molecular & Computational biology

Mar 26, 2024

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In a new study, scientists propose the concept of "virtual quantum broadcasting," which provides a workaround to the longstanding no-cloning theorem, thereby offering new possibilities for the transmission of quantum information.

Quantum computers promise to tackle some of the most challenging problems facing humanity today. While much attention has been directed towards the computation of quantum information, the transduction of information within ...

Condensed Matter

Mar 20, 2024

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Devices that capture the brilliant light from millions of quantum dots, including chip-scale lasers and optical amplifiers, have made the transition from laboratory experiments to commercial products. But newer types of quantum-dot ...

Optics & Photonics

Mar 19, 2024

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Scientists around the world work hard to rinse quantum systems for noise, which may disturb the function of tomorrow's powerful quantum computers. Researchers from the Niels Bohr Institute (NBI) have found a way to use noise ...

Quantum Physics

Mar 18, 2024

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In the quest to develop quantum computers and networks, there are many components that are fundamentally different than those used today. Like a modern computer, each of these components has different constraints. However, ...

Analytical Chemistry

Mar 11, 2024

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Two physicists at the University of Konstanz are developing a method that could enable the stable exchange of information in quantum computers. In the leading role: photons that make quantum bits "fly."

Optics & Photonics

Mar 6, 2024

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In quantum mechanics, **quantum information** is physical information that is held in the "state" of a quantum system. The most popular unit of quantum information is the qubit, a two-level quantum system. However, unlike classical digital states (which are discrete), a two-state quantum system can actually be in a superposition of the two states at any given time.

Quantum information differs from classical information in several respects, among which we note the following:

However, despite this, the amount of information that can be retrieved in a single qubit is equal to one bit. It is in the *processing* of information (quantum computation) that a difference occurs.

The ability to manipulate quantum information enables us to perform tasks that would be unachievable in a classical context, such as unconditionally secure transmission of information. Quantum information processing is the most general field that is concerned with quantum information. There are certain tasks which classical computers cannot perform "efficiently" (that is, in polynomial time) according to any known algorithm. However, a quantum computer can compute the answer to some of these problems in polynomial time; one well-known example of this is Shor's factoring algorithm. Other algorithms can speed up a task less dramatically - for example, Grover's search algorithm which gives a quadratic speed-up over the best possible classical algorithm.

Quantum information, and changes in quantum information, can be quantitatively measured by using an analogue of Shannon entropy. Given a statistical ensemble of quantum mechanical systems with the density matrix *S*, it is given by

Many of the same entropy measures in classical information theory can also be generalized to the quantum case, such as the conditional quantum entropy.

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