Quantum Types

Quantum typing in Qrisp is smoothly integrated into the typing infractructure of Python, implying it can be used to specify the types of function arguments and return values. By using quantum typing, developers can write more self-documenting code and improve the maintainability of their projects.

A quantum type in Qrisp is a subclass of QuantumVariable.

We include four basic built-in quantum types.

• QuantumFloat

• QuantumBool

• QuantumModulus

• QuantumChar

QuantumString is technically not a quantum type, since it inherits from QuantumArray but we still mention it here.

Creating custom quantum types

Creating a new quantum type within Qrisp is conveniently achieved by inheriting from QuantumVariable and modifying the decoder. In the following code snippet we demonstrate how to create a date quantum datatype using the datetime package.

import datetime
from qrisp import QuantumVariable

class QuantumDate(QuantumVariable):

    def __init__(self, size, starting_date):
        self.starting_date = starting_date
        QuantumVariable.__init__(self, size)

    def decoder(self, i):
        return self.starting_date + datetime.timedelta(i)


today = datetime.date.today()
tomorrow = today + datetime.timedelta(1)
even_later = today + datetime.timedelta(4)

#Create a QuantumDate instance
qd = QuantumDate(size = 3, starting_date = today)

#Initiate some wave function (amplitudes will be normalized)
qd[:] = {today : 1j, tomorrow : 0.5, even_later : -0.5}

Evaluate the measurement

>>> print(qd)
{datetime.date(2023, 3, 7): 0.6667, datetime.date(2023, 3, 8): 0.1667, datetime.date(2023, 3, 11): 0.1667}

Note

The results of the decoder have to be hashable.