Power

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Syntax

def power(exponent: CInt, stmt_block: QCallable) -> None:
    pass

​

Semantics

• If the statement block specifies the unitary operation $U$ on some quantum object, power applies $U^{exponent}$.
• In the general case, the statement block is iterated over exponent times, but in some important special cases the operation is implemented more efficiently.
• Quantum variables declared outside the power statement and used inside its nested block must be initialized prior to it and remain initialized subsequently.
• Quantum variables declared inside the power statement, including in nested function calls, must be uninitialized at the end of the statement.

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Examples

from classiq import *
from classiq.qmod.symbolic import pi


@qfunc
def foo(p: CInt, q: QBit):
    power(p, lambda: H(q))
    power(p, lambda: PHASE(pi / 8, q))


@qfunc
def main(q: Output[QBit]):
    allocate(q)
    power(2, lambda: foo(5, q))

qfunc foo(p: int, q: qbit) {
  power (p) {
    H(q);
  }
  power (p) {
    PHASE(pi / 8, q);
  }
}

qfunc main() {
  q: qbit;
  allocate(q);
  power (2) {
    foo(5, q);
  }
}