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).
The idea of state transfer is to develop schemes that allow the
transfer of an unknown quantum state from one location to another. Such
protocols might be very useful in the realisation of a practical quantum
computer because many physical interactions between qubits are short
range, and therefore only act on nearest-neighbours. To interact distant
qubits, they must first be moved next to each other.
The simplest state transfer protocol that one can consider is a
series of SWAP operations between pairs of nearest-neighbour qubits.
However, this requires a significant degree of control and, hence, it is
desireable to try and find other schemes which may be less complex and
therefore less prone to errors.
A number of schemes have now been developed that require a single,
time-independent, Hamiltonian to be applied between a series of qubits
quant-ph/0309131,quant-ph/0411020,quant-ph/0501007,quant-ph/0408152. One
particular example, from quant-ph/0309131, involves a Hamiltonian of the
form
H=\frac{1}{4}\sum_{n=1}^{N-1}\sqrt{n(N-n)}\left(\sigma_x^n\sigma_x^{n+1}+\sigma_y^n\sigma_y^{n+1}\right)
which is particularly simple because it commutes with the total spin
operator,
\sum_{n=1}^N\sigma_z^n
so we only have to examine what happens with an N × N matrix instead of
2N × 2N.
This particular Hamiltonian is even simpler because it is just the same
as the rotation matrix of a spin (N − 1)/2 particle.
Protocols have also been created that can accommodate errors in the
Hamiltonian, at the cost of some additional interaction at either end of
the transfer system quant-ph/0406112,quant-ph/0502186 and questions have
also been addressed as to the capacity of such systems
quant-ph/0312141.
Category:Miscellaneous
Last modified:
Monday, October 26, 2015 - 17:56
