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).
BQP, in
computational
complexity theory, stands for
"Bounded
error, Quantum,
Polynomial
time". It denotes the class of problems solvable by a
quantum
computer in polynomial time, with an error probability of at most
1/4 for all instances.
In other words, there is an
algorithm
for a quantum computer that is guaranteed to run in polynomial time. On
any given run of the algorithm, it has a probability of at most 1/4 that
it will give the wrong answer. That is true, whether the answer is YES
or NO.
The choice of 1/4 in the definition is arbitrary. Changing the
constant
to any
real
number k such that 0 < k < 1/2 does not change the
set
BQP. The idea is that there is a small
probability
of error, but running the algorithm many times produces an
exponentially-small
chance that the majority of the runs are wrong.
The number of
qubits
in the computer is allowed to be a
function
of the instance size. For example, algorithms are known for factoring an
n-bit integer using just over 2n qubits.
Quantum computers have gained widespread interest because some
problems of practical interest are known to be in BQP, but suspected to
be outside P. Currently, only three such problems are known:
This class is defined for a quantum computer. The corresponding class
for an ordinary
Turing
machine plus a source of randomness is
BPP.
BQP contains
P
and
BPP
and is contained in
PP
and
PSPACE.
In fact, BQP is
low
for PP, meaning that a PP machine
achieves no benefit from being able to solve BQP
problems instantly, an indication of the vast difference in power
between these similar classes.
Category:Computational
Complexity
Category:Quantum
Computation
Last modified:
Monday, October 26, 2015 - 17:56
