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85 lines
2.5 KiB
OCaml
85 lines
2.5 KiB
OCaml
(** A Slater determinant is expressed as a Waller-Hartree double determinant:
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{% $$
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D(\mathbf{R}) = D_\alpha(\mathbf{R_\alpha}) \times D_\beta(\mathbf{R_\beta})
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$$ %}
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The {% $\alpha$ %} and {% $\beta$ %} determinants are of type [Spindeterminant.t].
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*)
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type t
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type hole = int
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type particle = int
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(** {1 Accessors} *)
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val alfa : t -> Spindeterminant.t
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(** Get the {% $\alpha$ %} spin-determinant. *)
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val beta : t -> Spindeterminant.t
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(** Get the {% $\beta$ %} spin-determinant. *)
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val phase : t -> Phase.t
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(** Get the phase of the Slater determinant, the product of the phases of the
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spin-determinants.
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*)
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val is_none : t -> bool
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(** Tests if a Determinant is [None]. *)
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(** {1 Second quantization operators} *)
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val vac : int -> t
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(** Vacuum state, [vac = Some ]{% $|\rangle$ %}. The integer parameter is the size of the
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MO basis set. *)
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val creation : Spin.t -> particle -> t -> t
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(** [creation spin p] is the creation operator {% $a^\dagger_p$ %}. *)
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val annihilation : Spin.t -> hole -> t -> t
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(** [annihilation spin h] is the annihilation operator {% $a_h$ %}. *)
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val single_excitation : Spin.t -> hole -> particle -> t -> t
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(** Single excitation operator {% $T_h^p = a^\dagger_p a_h$ %}. *)
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val double_excitation : Spin.t -> hole -> particle -> Spin.t -> hole -> particle -> t -> t
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(** Double excitation operator {% $T_{hh'}^{pp'} = a^\dagger_p a^\dagger_{p'} a_{h'} a_h$ %}. *)
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val degree_alfa : t -> t -> int
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(** Returns degree of excitation between two determinants in the {% $\alpha$ %} spin. *)
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val degree_beta : t -> t -> int
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(** Returns degree of excitation between two determinants in the {% $\beta$ %} spin. *)
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val degrees : t -> t -> int*int
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(** Returns degrees of excitation between two determinants in {% $\alpha$ %} and
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{% $\beta$ %} spins as a pair. *)
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val degree : t -> t -> int
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(** Returns degree of excitation between two determinants. *)
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(** {1 Creators} *)
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val of_spindeterminants : Spindeterminant.t -> Spindeterminant.t -> t
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(** Creates a Slater determinant from an {% $\alpha$ %} and a {% $\beta$ %}
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[Spindeterminant.t].
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*)
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val of_lists : int -> int list -> int list -> t
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(** Creates a Slater determinant from a two lists of orbital indices.
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The integer parameter is the size of the MO basis set. *)
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val negate_phase : t -> t
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(** Returns the same determinant with the phase negated. *)
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(** {1 Printers} *)
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val pp_det : int -> Format.formatter -> t -> unit
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(** First [int] is the number of MOs to print. *)
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(** {1 Unit tests} *)
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val test_case : unit -> (string * [> `Quick ] * (unit -> unit)) list
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