Researchers 'teleport' a quantum gate

September 5, 2018, Yale University
Network overview of the modular quantum architecture demonstrated in the new study. Credit: Yale University

Yale University researchers have demonstrated one of the key steps in building the architecture for modular quantum computers: the "teleportation" of a quantum gate between two qubits, on demand.

The findings appear online Sept. 5 in the journal Nature.

The key principle behind this new work is quantum teleportation, a unique feature of quantum mechanics that has previously been used to transmit unknown quantum states between two parties without physically sending the state itself. Using a theoretical protocol developed in the 1990s, Yale researchers experimentally demonstrated a quantum operation, or "gate," without relying on any direct interaction. Such gates are necessary for quantum computation that relies on networks of separate quantum systems—an architecture that many researchers say can offset the errors that are inherent in quantum computing processors.

Through the Yale Quantum Institute, a Yale research team led by principal investigator Robert Schoelkopf and former graduate student Kevin Chou is investigating a modular approach to quantum computing. Modularity, which is found in everything from the organization of a biological cell to the network of engines in the latest SpaceX rocket, has proved to be a powerful strategy for building large, complex systems, the researchers say. A quantum modular architecture consists of a collection of modules that function as small quantum processors connected into a larger network.

Modules in this architecture have a natural isolation from each other, which reduces unwanted interactions through the larger system. Yet this isolation also makes performing operations between modules a distinct challenge, according to the researchers. Teleported gates are a way to implement inter-module operations.

"Our work is the first time that this protocol has been demonstrated where the classical communication occurs in real-time, allowing us to implement a 'deterministic' operation that performs the desired operation every time," Chou said.

Fully useful quantum computers have the potential to reach computation speeds that are orders of magnitude faster than today's supercomputers. Yale researchers are at the forefront of efforts to develop the first fully useful quantum computers and have done pioneering work in with superconducting circuits.

Quantum calculations are done via delicate bits of data called qubits, which are prone to errors. In experimental quantum systems, "logical" qubits are monitored by "ancillary" qubits in order to detect and correct errors immediately. "Our experiment is also the first demonstration of a two- operation between logical qubits," Schoelkopf said. "It is a milestone toward information processing using error-correctable qubits."

Explore further: Experimentally demonstrated a toffoli gate in a semiconductor three-qubit system

More information: Kevin S. Chou et al. Deterministic teleportation of a quantum gate between two logical qubits, Nature (2018). DOI: 10.1038/s41586-018-0470-y

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2.3 / 5 (3) Sep 06, 2018

Quantum entangled particles for communication and data storage.
3.4 / 5 (5) Sep 06, 2018
Quantum entangled particles for communication

Read up on QM. Entanglement is not useful for communication or storage.
Entaglement is useful for manipulation - like the above mentioned gates - and stuff like encryption, because these operations do not constitute information.

Information is a measure of the correlation between a SET state at the origin and a MEASURED state at the destination.
Entanglement does not allow the SET operation. The state at the origin remains undefined (otherwise entanglement is broken). You cannot encode information onto an undefined state.

not rated yet Sep 06, 2018
Is it possible to send a message back in time using a quantum network?
1 / 5 (2) Sep 06, 2018
If entanglement not useful in communication, you had better let at least the Austrians know the financial bank transaction system based on entanglement has never worked 10 years and they must be in default.
5 / 5 (1) Sep 06, 2018
Is it possible to send a message back in time using a quantum network?

Don't I wish!
1 / 5 (1) Sep 06, 2018
The two key problems I see with quantum time-travel communications?

First, The technology you are using did not exist in the past to receive the message.

Second, if you could get around that first problem? The "older" you who received the message from the "newer" you? Would change their "future" you, Prior knowledge of such a communication would change the "newer" you into a "newest" you.

What happened to the original "newer" you? Only one way to find out!

Good bye! Good Luck!

Over the years I have amused myself speculating that dreams, delusions, miracles, fantasies, etc; were possibly quantum signals from future humans. Leakage from their quantum broadcasts of future popular children's entertainment.
Phyllis Harmonic
5 / 5 (1) Sep 06, 2018
If entanglement not useful in communication, you had better let at least the Austrians know the financial bank transaction system based on entanglement has never worked 10 years and they must be in default.

Your are referring the the BB84 quantum key distribution protocol which does not rely on entanglement but rather, Heisenberg uncertainty. This (and other QKD protocols) require key verification via classical channels so are useful only for *securing* the communication channel, not for communicating information.
Phyllis Harmonic
5 / 5 (1) Sep 06, 2018

Quantum entangled particles for communication and data storage.

Completely overlooks the limits imposed by Heisenberg uncertainty and the necessary conversion to classical channels for information exchange. Also, you cannot verify any quantum exchange by using another quantum exchange (the No Cloning Theorem).

In the cited article the author veers off into new-age woo, e.g.:

"The state of a universe that is considered to be unified and joined together holistically, through a process of non-local resonance occurring within the underlying zero-point field, that connects all matter, energy and information in the cosmos."

And this: "Entangled Particle Holographics suggests that all things in the universe are interconnected informationally." which is simply hogwash for the reason antialias_physorg has provided up-thread.

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