qrisp.QuantumFloat.quantum_bit_shift

QuantumFloat.quantum_bit_shift(shift_amount: int | QuantumFloat) → None

Performs a bit shift in the quantum device.

While exp_shift performs a bit shift in the compiler (thus costing no quantum gates), this method performs the bit shift on the hardware.

This has the advantage that it can be controlled if called within a ControlEnvironment and furthermore admits bit shifts based on the state of a QuantumFloat.

Note

Bit shifts based on a QuantumFloat are currently only possible if both self and shift_amount are unsigned.

Warning

Quantum bit shifting extends the QuantumFloat (ie. it allocates additional qubits).

Parameters:

shift_amountint or QuantumFloat

The amount to shift.

Raises:

TypeError

Tried to shift QuantumFloat exponent by non-integer value

Exception

Quantum-quantum bitshifting is currently only supported for unsigned arguments

Examples

We create a QuantumFloat and a QuantumBool to perform a controlled bit shift, then evaluate the resulting (superposed) state:

from qrisp import QuantumFloat, QuantumBool, h
qf = QuantumFloat(4)
qf[:] = 1
qbl = QuantumBool()
h(qbl)

with qbl:
    qf.quantum_bit_shift(2)

print(qf.qs.statevector())
# Yields
# sqrt(2)*(|1>*|False> + |4>*|True>)/2