BlockEncoding.__neg__

BlockEncoding.__neg__() → BlockEncoding

Returns a BlockEncoding of the negated operator.

This method implements the transformation \(A \to -A\) by scaling the encoded operator by \(-1\).

Returns:

BlockEncoding

A new BlockEncoding instance representing the operator \(-A\).

Examples

Define a block-encoding and negate it.

from qrisp import *
from qrisp.block_encodings import BlockEncoding
from qrisp.operators import X, Y, Z

H1 = X(0)*X(1) - 0.2*Y(0)*Y(1)
H2 = 0.2*Y(0)*Y(1) - X(0)*X(1)

BE1 = BlockEncoding.from_operator(H1)
BE2 = BlockEncoding.from_operator(H2)
BE3 = -BE1

def operand_prep():
    qv = QuantumFloat(3)
    return qv

@terminal_sampling
def main(BE):
    qv = BE.apply_rus(operand_prep)()
    return qv

res_be2 = main(BE2)
res_be_neg = main(BE3)

print("Result from BE of H2 = - H1: ", res_be2)
print("Result from - BE1: ", res_be_neg)
# Result from BE of H2 = - H1:  {3.0: 1.0}
# Result from - BE1:  {3.0: 1.0}