vc

◼ vc[...]is a wrapper (vector) that holds the information about the occupancy of the individual sites in the occupation number representation.

◼ Function vacuum returns the vc vector of all zeros.

◼ vc objects are usually manipulated using function ap.

◼ See also: basis, makebasis, op2ndx, ndx2op, goodopQ, vacuum, ap, vc2ops.

Further examples

Load sneg and declare some quantities

<< sneg`sneg`;
snegfermionoperators[c, d];

Construct a basis for two lattice sites c and d, and obtain the vacuum state

makebasis[{c[], d[]}]
vac = vacuum[]

Vaccum state internal representation

FullForm[vac]

Single-particle states and multi-particle states

p1 = ap[c[CR, UP], vac]
FullForm[%]
p12 = ap[nc[c[CR, UP], c[CR, DO]], vac]
FullForm[%]
p14 = ap[nc[c[CR, UP], d[CR, DO]], vac]
FullForm[%]

vc vectors can also contain Dirac kets

ap[ket[a], p1]
ap[ket[a], p12]
ap[ket[a], p14]

conj applied to a vc vector returns unevaluated. Nevertheless, scalar products can be computed in this manner.

conj[p1]
nc[conj[p1], p1]
conj[p14]
nc[conj[p14], p14]

    
nc[conj[p1], p14]
nc[conj[p14], p1]