Error message
- Deprecated function: TYPO3\PharStreamWrapper\Manager::initialize(): Implicitly marking parameter $resolver as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::initialize(): Implicitly marking parameter $collection as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::__construct(): Implicitly marking parameter $resolver as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::__construct(): Implicitly marking parameter $collection as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: UpdateQuery::expression(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: MergeQuery::expression(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryInterface::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryInterface::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryExtender::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryExtender::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQuery::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQuery::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
In
quantum
information science, classical information channel
(often called simply classical channel) is a
communication
channel that can be used to transmit classical information (as
opposed to quantum channel which can transmit quantum information). An
example would be a light travelling over fiber optics lines or
electricity travelling over phone lines.
Although classical channels cannot transmit quantum information by
themselves, they can be useful in combination with quantum channels.
Examples of their use are:
- In
quantum
teleportation, a classical channel together with a previously
prepared
entangled
quantum state are used to transmit quantum information between two
parties. Neither the classical channel nor the previously prepared
quantum state alone can do this task.
- In
quantum
cryptography, a classical channel is used along with a quantum
channel in protocols for quantum key exchange.
- In
quantum
communication, the information rate of a noisy quantum channel can
be increased when used together with a noise-free classical channel. In
particular, some very noisy quantum channels cannot transmit quantum
information if used alone but can transmit it if used together with a
classical channel (which is not capable of transmitting quantum
information by itself).
- In
quantum
entanglement, classical channels can be used to transform an
existing entangled state into a different entangled state, but they
cannot create entangled states.
References
- M. Nielsen, I. Chuang. Quantum computation and quantum information.
Cambridge University Press, 2000.
Category:Quantum
Communication
Category:Quantum
Information Theory
Last modified:
Monday, October 26, 2015 - 17:56
