org.mathIT.quantum

Class QuantumGate

java.lang.Object

org.mathIT.quantum.QuantumGate

All Implemented Interfaces:

Serializable

public class QuantumGate
extends Object
implements Serializable

This class encodes an elementary quantum gate. It is the central class for the design of quantum circuits and is used to determine the sequence of quantum operations. The initial state of a quantum circuit is considered as a special quantum gate, the "initialState" gate. It is a classical state for which each qubit either has the value |0> or |1>.

Version:

1.5

Author:

Andreas de Vries

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
String	axis The axis of rotation, if this gate represents a qubit rotation.
FunctionParser	function the parsed function for the function evaluation gate Uf.
String	name specifies the name of this quantum gate.
int	phiAsPartOfPi rotation angle, as the integral part n of π.
int[]	qubits specifies the index of qubits on which the gate operates.
boolean	yRegister specifies if the gate operates on the y-register.

Constructor Summary

Constructors

Constructor and Description
QuantumGate(String name, int[] qubits, boolean yRegister) Constructs a generic quantum gate.
QuantumGate(String name, int[] qubits, FunctionParser function, boolean yRegister) Constructor for a quantum gate evaluating a function.
QuantumGate(String name, int[] qubits, String axis, int phiAsPartOfPi, boolean yRegister) Constructor for a rotation operation.

Method Summary

Modifier and Type	Method and Description
String	getName() Returns the name of this quantum gate.
int[]	getQubits() Returns an array of the indices of the qubits on which this gate operates.
static boolean	isValid(String name) Checks whether the specified string represents a valid quantum gate.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

name

public String name

specifies the name of this quantum gate. It is uniquely related to a quantum operation.

qubits

public int[] qubits

specifies the index of qubits on which the gate operates. For a controlled gate, the last entry always is the target qubit. However, for a Grover operator gate, this field is abused to specify the "needle", i.e., the value which is known to the oracle but which can only be found after successive Grover iterations.

yRegister

public boolean yRegister

specifies if the gate operates on the y-register. If not, the x-register is acted on.

function

public FunctionParser function

the parsed function for the function evaluation gate U_f. It is null for all other gates.

axis

public String axis

The axis of rotation, if this gate represents a qubit rotation.

phiAsPartOfPi

public int phiAsPartOfPi

rotation angle, as the integral part n of π. More accurately, n = π/φ where φ is the rotation angle in radians.

Constructor Detail

QuantumGate

public QuantumGate(String name,
                   int[] qubits,
                   boolean yRegister)

Constructs a generic quantum gate.

Parameters:

name - the name of the quantum gate; possible values are determined by Circuit.gatelist

qubits - array representing the state of the qubits

yRegister - flag indicating whether the gate applies to the y-register

Throws:

IllegalArgumentException - if the gate name is unknown

QuantumGate

public QuantumGate(String name,
                   int[] qubits,
                   FunctionParser function,
                   boolean yRegister)

Constructor for a quantum gate evaluating a function.

Parameters:

name - the name of the quantum gate; possible values are determined by Circuit.gatelist

qubits - array representing the state of the qubits

function - the function to be evaluated

yRegister - flag indicating whether the gate applies to the y-register

Throws:

IllegalArgumentException - if the gate name is unknown or the function is null

QuantumGate

public QuantumGate(String name,
                   int[] qubits,
                   String axis,
                   int phiAsPartOfPi,
                   boolean yRegister)

Constructor for a rotation operation.

Parameters:

name - the name of the quantum gate; possible values are determined by Circuit.gatelist

qubits - array representing the state of the qubits

axis - the axis of rotation, i.e., "x", "y", or "z"

phiAsPartOfPi - rotation angle, as the integral part n of π; more accurately, n = π/φ where φ is the rotation angle in radians.

yRegister - indicates whether this gate belngs to the y-register

Throws:

IllegalArgumentException - if the gate name is unknown

Method Detail

getName

public String getName()

Returns the name of this quantum gate.

Returns:

the name of this quantum gate

getQubits

public int[] getQubits()

Returns an array of the indices of the qubits on which this gate operates. For gates acting on a single qubit, such as a Hadamard or a Pauli gate, the array has length 1 and contains the index of its qubit. For a controlled gate, the last entry always is the target qubit.

Returns:

the indices of the qubits this quantum gate operates upon

isValid

public static boolean isValid(String name)

Checks whether the specified string represents a valid quantum gate.

Parameters:

name - the name to be checked

Returns:

true if and only if the name represents a valid quantum gate