Straightening messy correlations with a quantum comb

Nov 23, 2009
Physicists have shown that complicated quantum entanglements can be transformed into an arrangement where the entanglement fans out neatly from the hub qubit to each of the other qubits. Credit: Dong Yang and Jens Eisert

Quantum computing promises ultra-fast communication, computation and more powerful ways to encrypt sensitive information. But trying to use quantum states as carriers of information is an extremely delicate business. Now two physicists have shown, mathematically, how to gently tease out unwanted knots in quantum communication, while keeping the information intact. Their work is reported in the current issue of Physical Review Letters and highlighted with a Viewpoint in Physics.

When two particles are entangled, they effectively act as a single entity, even though they might be on opposite ends of the galaxy. Physicists can code information into particles to make , or qubits, then entangle the qubits in an orderly fashion to form an entangled bit, or ebit. Ebits can then be used to create incredibly tough codes or teleport information between two distant systems. But messy entanglements among particles make qubits more susceptible to losing their encoded information.

Now Dong Yang and Jens Eisert of the University of Potsdam have shown how to delicately comb out a snarl of entanglements among many qubits while keeping the information intact. They designate one as a hub and then use a combination of two existing quantum protocols to transform the original cat's cradle into an arrangement where entanglement fans out neatly from the hub qubit to each of the other qubits.

This looks like a primitive model for a quantum World Wide Web: individual users each form an ebit with a single quantum search engine, and send queries and receive results via quantum teleportation.

More information: Dong Yang and Jens Eisert, Phys. Rev. Lett. 103, 220501 (2009) - Published November 23, 2009, Download PDF (free)

Source: American Physical Society

Explore further: Unleashing the power of quantum dot triplets

add to favorites email to friend print save as pdf

Related Stories

Creating a six-qubit cluster state

Nov 02, 2009

(PhysOrg.com) -- Many scientists believe that quantum entanglement is required in order for effective quantum computing. Entanglement takes place when there is a connection that exists between two objects - even when they ...

A Quantum CPU: the Pentium Q?

May 23, 2006

A new design scheme for a quantum processor core makes potential quantum computers more technically feasible, more efficient, and in many cases faster by keeping all of the quantum bits active all the time, rather than switching ...

2 qubits in action, new step towards the quantum computer

Jun 14, 2007

Researchers at Delft University of Technology have succeeded in carrying out calculations with two quantum bits, the building blocks of a possible future quantum computer. The Delft researchers are publishing ...

Quantum Communication Over Flawed Networks may be Possible

Dec 14, 2007

If successfully implemented, quantum communication could be an extremely secure method of transmitting information – but there are major roadblocks to pass. Recently, physicists suggested a way, at least in theory, to overcome ...

Recommended for you

Unleashing the power of quantum dot triplets

9 hours ago

Quantum computers have yet to materialise. Yet, scientists are making progress in devising suitable means of making such computers faster. One such approach relies on quantum dots—a kind of artificial atom, ...

Exotic state of matter propels quantum computing theory

Jul 23, 2014

So far it exists mainly in theory, but if invented, the large-scale quantum computer would change computing forever. Rather than the classical data-encoding method using binary digits, a quantum computer would process information ...

Quantum leap in lasers brightens future for quantum computing

Jul 22, 2014

Dartmouth scientists and their colleagues have devised a breakthrough laser that uses a single artificial atom to generate and emit particles of light. The laser may play a crucial role in the development of quantum computers, ...

Boosting the force of empty space

Jul 22, 2014

Vacuum fluctuations may be among the most counter-intuitive phenomena of quantum physics. Theorists from the Weizmann Institute (Rehovot, Israel) and the Vienna University of Technology propose a way to amplify ...

User comments : 0