News tagged with quantum communication

Trade-off coding for quantum communication provides more benefits than previously thought

(Phys.org) -- In optical communication systems, the overall performance depends on the strategy used to transmit photons from one location to another. In previous attempts to optimize this performance, scientists ...

Physics / Quantum Physics

created Apr 16, 2012 | popularity 4.4 / 5 (9) | comments 0 | with audio podcast feature

New way to store light could prove useful for optical communication

(PhysOrg.com) -- Due to its high data carrying capacity and low loss, light can serve as an ideal information carrier. However, due to the high speed at which it travels, light is difficult to store. Because ...

Physics / Optics & Photonics

created Oct 03, 2011 | popularity 4 / 5 (10) | comments 3 | with audio podcast feature

Physicists describe how to make time-reversed light pulses

(PhysOrg.com) -- By taking advantage of the properties of periodic systems, physicists have described how to efficiently time-reverse ultrashort electromagnetic pulses. Since a time-reversed pulse evolves ...

Physics / General Physics

created May 31, 2011 | popularity 4.4 / 5 (17) | comments 44 | with audio podcast feature

Proposed experiment offers new way to generate macroscopic entanglement

(PhysOrg.com) -- In the development of quantum information processing, one of the key requirements is achieving quantum entanglement. But recently, physicists have been investigating other forms of quantum correlations besides ...

Physics / Quantum Physics

created Jan 05, 2012 | popularity 4.9 / 5 (20) | comments 2 | with audio podcast report

Entanglement can help in classical communication

(PhysOrg.com) -- When most of us think of entanglement, our minds jump immediately to quantum communication. "Entanglement has become very well known and useful in quantum communication," Robert Prevedel tells PhysOrg.com. Preved ...

Physics / General Physics

created Mar 30, 2011 | popularity 4.3 / 5 (17) | comments 14 | with audio podcast feature

Reducing noise in quantum operation at room temperature

(PhysOrg.com) -- "A quantum memory is a crucial component of future quantum information processing technologies. Among these technologies, a quantum communications system based on light will enable vastly improved performance ...

Physics / Quantum Physics

created Aug 23, 2011 | popularity 5 / 5 (4) | comments 3 | with audio podcast feature

Vertical cavity quantum switch could lead us away from electronics-based computing

(PhysOrg.com) -- Right now, many researchers around the world are working on ways to move away from electronics-dominated computing systems. There are a number of ideas about how this can be accomplished. "We are trying to ...

Physics / Optics & Photonics

created Jun 30, 2011 | popularity 4.4 / 5 (27) | comments 5 | with audio podcast feature

Physicists offer countermeasure to new quantum eavesdropping attack

(PhysOrg.com) -- As early communications systems using quantum cryptography become commercially available, physicists have been investigating new types of security attacks in an effort to defend against them. ...

Physics / Quantum Physics

created Jul 25, 2011 | popularity 3.9 / 5 (9) | comments 0 | with audio podcast feature

Long-distance quantum communication gets closer as physicists increase light storage efficiency by an order of magnitude

(PhysOrg.com) -- In a new demonstration of reversible light storage, physicists have achieved storage efficiencies of more than a magnitude greater than those offered by previous techniques. The new method could be useful ...

Physics / Quantum Physics

created Mar 01, 2010 | popularity 4.2 / 5 (25) | comments 10 | with audio podcast feature

Single photon solid-state memory for telecommunications

(PhysOrg.com) -- One of the issues associated with quantum information schemes revolves around the ability to develop quantum memories that allow for the retrieval of information on demand. Overcoming this ...

Physics / Quantum Physics

created Mar 08, 2010 | popularity 4.6 / 5 (20) | comments 5 | with audio podcast feature

Researchers Set New Distance Record for Quantum Key Distribution

(PhysOrg.com) -- Quantum key distribution (QKD) could be the next commercial success of quantum physics, and a recent study has taken the field a step closer to this reality. Researchers from the University ...

Physics / Quantum Physics

created Jul 21, 2009 | popularity 4.9 / 5 (14) | comments 4 feature

Nanotube-based terahertz polarizer nears perfection

(PhysOrg.com) -- Researchers at Rice University are using carbon nanotubes as the critical component of a robust terahertz polarizer that could accelerate the development of new security and communication ...

Nanotechnology / Nanophysics

created Jan 30, 2012 | popularity 4.5 / 5 (11) | comments 1 | with audio podcast

Post-Quantum Correlations: Exploring the Limits of Quantum Nonlocality

(PhysOrg.com) -- When it comes to nonlocal correlations, some correlations are more nonlocal than others. As the subject of study for several decades, nonlocal correlations (for example, quantum entanglement) ...

Physics / Quantum Physics

created May 07, 2009 | popularity 4 / 5 (22) | comments 20 feature

Beam me up ... Quantum teleporter breakthrough

(PhysOrg.com) -- Researchers have achieved a breakthrough in quantum communications and computing using a teleporter and a paradoxical cat.

Physics / Quantum Physics

created Apr 15, 2011 | popularity 4.2 / 5 (46) | comments 48 | with audio podcast

Nanocrystal infrared LEDs can be made cheaply

(Phys.org) -- Light-emitting diodes at infrared wavelengths are the magic behind such things as night vision and optical communications, including the streaming data that comes through Netflix. Cornell researchers have advanced ...

Nanotechnology / Nanomaterials

created May 10, 2012 | popularity 5 / 5 (4) | comments 0 | with audio podcast

Quantum channel

In quantum information theory, a quantum channel is a communication channel which can transmit quantum information, as well as classical information. An example of quantum information is the state of a qubit. An example of classical information is a text document transmitted over the internet.

More formally, quantum channels are completely positive, trace preserving maps between spaces of operators, as defined more precisely below.

For more information about Quantum channel, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.

Related topics: quantum information