uni20::models Namespace Reference

Classes
struct	SpinHalfU1Site
	U(1)-symmetric spin-half local space and its two state charges. More...

Typedefs
template<RealOrComplex Scalar>
using	SpinHalfU1Mpo = tensor_network::FiniteMpo< Scalar, LocalSpace, LocalSpace, PackedSparseBlockStorage<> >
	Packed finite MPO type produced by the spin-half model builders.
template<RealOrComplex Scalar, BlockTensorStorage Storage = PackedSparseBlockStorage<>>
using	SpinHalfU1Mps = tensor_network::FiniteMps< Scalar, BlockSpace, LocalSpace, Storage >
	Finite MPS type produced by the spin-half model builders.

Enumerations
enum class	SpinHalfState { up , down }
	Physical state selected at the first site of a spin-half product pattern. More...

Functions
template<RealOrComplex Scalar = double, BlockTensorStorage Storage = PackedSparseBlockStorage<>> requires ImmediateLocalBlockStorageFor<Storage, Scalar, 3, 2>
auto	make_neel_product_mps (std::size_t length, SpinHalfU1Site const &local, SpinHalfState first=SpinHalfState::up) -> SpinHalfU1Mps< Scalar, Storage >
	Construct a normalized alternating spin-half product MPS.
template<RealOrComplex Scalar = double>
auto	make_spin_half_heisenberg_mpo (std::size_t length, SpinHalfU1Site const &local, make_real_t< Scalar > exchange=make_real_t< Scalar >{1}, make_real_t< Scalar > longitudinal_field=make_real_t< Scalar >{}) -> SpinHalfU1Mpo< Scalar >
	Construct the open spin-half Heisenberg Hamiltonian as a finite MPO.
auto	make_spin_half_u1_site (std::string_view charge_name="Sz") -> SpinHalfU1Site
	Construct the standard U(1)-symmetric spin-half local space.

Typedef Documentation

SpinHalfU1Mpo

template<RealOrComplex Scalar>

using uni20::models::SpinHalfU1Mpo = typedef tensor_network::FiniteMpo<Scalar, LocalSpace, LocalSpace, PackedSparseBlockStorage<> >

Packed finite MPO type produced by the spin-half model builders.

SpinHalfU1Mps

template<RealOrComplex Scalar, BlockTensorStorage Storage = PackedSparseBlockStorage<>>

using uni20::models::SpinHalfU1Mps = typedef tensor_network::FiniteMps<Scalar, BlockSpace, LocalSpace, Storage>

Finite MPS type produced by the spin-half model builders.

Template Parameters

Scalar	Real or complex tensor element type.
Storage	Block storage policy used by every MPS site.

Enumeration Type Documentation

SpinHalfState

enum class uni20::models::SpinHalfState

strong

Physical state selected at the first site of a spin-half product pattern.

Enumerator
up
down

Function Documentation

make_neel_product_mps()

template<RealOrComplex Scalar = double, BlockTensorStorage Storage = PackedSparseBlockStorage<>>
requires ImmediateLocalBlockStorageFor<Storage, Scalar, 3, 2>

auto uni20::models::make_neel_product_mps	(	std::size_t	length,
		SpinHalfU1Site const &	local,
		SpinHalfState	first = SpinHalfState::up
	)		-> SpinHalfU1Mps<Scalar, Storage>

Construct a normalized alternating spin-half product MPS.

Every bond contains one cumulative-charge sector of dimension one, and every site contains one scalar block with value one. The resulting product state is canonical from either direction.

Template Parameters

Scalar	Real or complex MPS element type.
Storage	Immediate local block storage policy used by every MPS site.

Parameters

length	Positive number of sites.
local	U(1) spin-half local space.
first	State placed on site zero; later sites alternate.

Returns

Finite MPS in the corresponding total-charge sector.

Exceptions

std::invalid_argument

If length is zero.

make_spin_half_heisenberg_mpo()

template<RealOrComplex Scalar = double>

auto uni20::models::make_spin_half_heisenberg_mpo	(	std::size_t	length,
		SpinHalfU1Site const &	local,
		make_real_t< Scalar >	exchange = make_real_t<Scalar>{1},
		make_real_t< Scalar >	longitudinal_field = make_real_t<Scalar>{}
	)		-> SpinHalfU1Mpo<Scalar>

Construct the open spin-half Heisenberg Hamiltonian as a finite MPO.

The Hamiltonian is exchange * sum_i S_i.S_(i+1) + longitudinal_field * sum_i S_i^z. Interior auxiliaries use [start, pending S-, pending S+, pending Sz, finish] with charges [0,-1,+1,0,0]. Both boundary auxiliaries contain only the scalar charge, so boundary index zero is the complete open-chain contraction.

Template Parameters

Scalar

Real or complex MPO element type.

Parameters

length	Positive number of sites.
local	U(1) spin-half local space.
exchange	Nearest-neighbor exchange coefficient.
longitudinal_field	On-site longitudinal field coefficient.

Returns

Packed finite MPO with reduced one-state boundaries.

Exceptions

std::invalid_argument

If length is zero.

make_spin_half_u1_site()

auto uni20::models::make_spin_half_u1_site ( std::string_view  charge_name = "Sz" ) -> SpinHalfU1Site

inline

Construct the standard U(1)-symmetric spin-half local space.

Parameters

charge_name

Name of the conserved U(1) component, normally "Sz".

Returns

Local state space and charges in up-then-down order.

Exceptions

std::invalid_argument

If charge_name is empty.