State

Base class for all quantum state representations.

Factories

state_vector(const RealMatrix vector) -> State

State vector factory.

Provides a way to construct a state vector by specifying a vector of coefficients.

Parameters

• vector: Vector of coefficients.

Example

// A state vector may be constructed as follows:
var state = state_vector(vector([0,0,0,0]), as_spinhalf) // Returns a default state vector that stores 4 coefficients identically equal to zero. The default StateInfo option is as_complex | as_dense | as_abstract | as_complete

state_vector(const ComplexMatrix vector) -> State

State vector factory.

Provides a way to construct a state vector by specifying a vector of coefficients.

Parameters

• vector: Vector of coefficients.

Example

// A state vector may be constructed as follows:
var state = state_vector(vector([0,0,0,0]), as_spinhalf) // Returns a default state vector that stores 4 coefficients identically equal to zero. The default StateInfo option is as_complex | as_dense | as_abstract | as_complete

state_vector(integer num_sites) -> State

State vector factory.

Provides a way to construct a state vector by providing a number of sites.

Parameters

• num_sites: The number of sites that compose the Hilbert space of the state vector.

Example

var state = state_vector(10, as_real | as_spinhalf) // Returns a default state vector that stores $2^{10}$ coefficients identically set to zero. The default StateInfo option is as_complex | as_dense | as_abstract | as_complete

state_vector(const RealMatrix vector, as_real options) -> State

State vector factory.

Provides a way to construct a state vector by providing a vector of coefficients and a StateInfo option.

Parameters

• vector: Vector of coefficients.
• options: State vector options.

Example

var options = as_spinhalf | as_complex  // Returns a StateInfo option.
var state = state_vector(vector([0,0,0,0]), options) // Returns a complex spinhalf state vector that stores 4 coefficients identically equal to zero.

state_vector(const RealMatrix vector, as_complex options) -> State

State vector factory.

Provides a way to construct a state vector by providing a vector of coefficients and a StateInfo option.

Parameters

• vector: Vector of coefficients.
• options: State vector options.

Example

var options = as_spinhalf | as_complex  // Returns a StateInfo option.
var state = state_vector(vector([0,0,0,0]), options) // Returns a complex spinhalf state vector that stores 4 coefficients identically equal to zero.

state_vector(const RealMatrix vector, const StateInfo options) -> State

State vector factory.

Provides a way to construct a state vector by providing a vector of coefficients and a StateInfo option.

Parameters

• vector: Vector of coefficients.
• options: State vector options.

Example

var options = as_spinhalf | as_complex  // Returns a StateInfo option.
var state = state_vector(vector([0,0,0,0]), options) // Returns a complex spinhalf state vector that stores 4 coefficients identically equal to zero.

state_vector(const ComplexMatrix vector, as_complex options) -> State

State vector factory.

Provides a way to construct a state vector by providing a vector of coefficients and a StateInfo option.

Parameters

• vector: Vector of coefficients.
• options: State vector options.

Example

var options = as_spinhalf | as_complex  // Returns a StateInfo option.
var state = state_vector(vector([0,0,0,0]), options) // Returns a complex spinhalf state vector that stores 4 coefficients identically equal to zero.

state_vector(const ComplexMatrix vector, const StateInfo options) -> State

State vector factory.

Provides a way to construct a state vector by providing a vector of coefficients and a StateInfo option.

Parameters

• vector: Vector of coefficients.
• options: State vector options.

Example

var options = as_spinhalf | as_complex  // Returns a StateInfo option.
var state = state_vector(vector([0,0,0,0]), options) // Returns a complex spinhalf state vector that stores 4 coefficients identically equal to zero.

state_vector(integer num_sites, const StateInfo options) -> State

State vector factory.

Provides a way to construct a state vector by providing a number of sites and a StateInfo option.

Parameters

• num_sites: The number of sites that compose the Hilbert space of the state vector.
• options: State vector options.

Example

var options = as_spinhalf | as_real  // Returns a StateInfo option.
var state = state_vector(10, options) // Returns a real spinhalf state vector that stores $2^{10}$ coefficients.

state_vector(integer num_sites, as_real options) -> State

State vector factory.

Provides a way to construct a state vector by providing a number of sites and a StateInfo option.

Parameters

• num_sites: The number of sites that compose the Hilbert space of the state vector.
• options: State vector options.

Example

var options = as_spinhalf | as_real  // Returns a StateInfo option.
var state = state_vector(10, options) // Returns a real spinhalf state vector that stores $2^{10}$ coefficients.

state_vector(integer num_sites, as_complex options) -> State

State vector factory.

Provides a way to construct a state vector by providing a number of sites and a StateInfo option.

Parameters

• num_sites: The number of sites that compose the Hilbert space of the state vector.
• options: State vector options.

Example

var options = as_spinhalf | as_real  // Returns a StateInfo option.
var state = state_vector(10, options) // Returns a real spinhalf state vector that stores $2^{10}$ coefficients.

Symbols

Name	Description
!=	Checks inequality between two states.
*	Multiplies a quantum state by a constant coefficient.
*=	Multiplies the state by a constant coefficient.
-	Subtracts two state vectors.
/	Divides a quantum state by a constant coefficient.
/=	Divides the state by a constant coefficient.
==	Checks equality between two states.

Members

Name	Description
conjugate	Computes the complex conjugate of the quantum state.
dimension	Returns the dimension of the basis state at the given site.
dot	Computes the inner product between two quantum states.
info	Returns the StateInfo of the current state.
norm	Computes the norm of the quantum state.
size	Returns the total number of coefficients needed to represent the state.
squared_norm	Computes the squared norm of the quantum state.