Pairstate basis calculations¶
Preliminaries¶
Relative orientation of the two atoms can be described with polar angle \(\theta\) (range \(0\pi\)) and azimuthal angle \(\phi\) (range \(02\pi\)). The \(\hat{z}\) axis is here specified relative to the laser driving. For circularly polarized laser light, this is the direction of laser beam propagation. For linearly polarized light, this is the plane of the electric field polarization, perpendicular to the laser direction.
Internal coupling between the two atoms in \(n,l,j,m_1\rangle\) and \(nn,ll,jj,m_2\rangle\) is calculated easily for the two atoms positioned so that \(\theta = 0\), and for other angles wignerD matrices are used to change a basis and perform calculation in the basis where couplings are more clearly seen.
Overview¶
PairStateInteractions Methods
PairStateInteractions.defineBasis (theta, …) 
Finds relevant states in the vicinity of the given pairstate 
PairStateInteractions.getC6perturbatively (…) 
Calculates \(C_6\) from second order perturbation theory. 
PairStateInteractions.getLeRoyRadius () 
Returns Le Roy radius for initial pairstate. 
PairStateInteractions.diagonalise (rangeR, …) 
Finds eigenstates in atom pair basis. 
PairStateInteractions.plotLevelDiagram ([…]) 
Plots pair state level diagram 
PairStateInteractions.showPlot ([interactive]) 
Shows level diagram printed by PairStateInteractions.plotLevelDiagram 
PairStateInteractions.exportData (fileBase[, …]) 
Exports PairStateInteractions calculation data. 
PairStateInteractions.getC6fromLevelDiagram (…) 
Finds \(C_6\) coefficient for original pair state. 
PairStateInteractions.getC3fromLevelDiagram (…) 
Finds \(C_3\) coefficient for original pair state. 
PairStateInteractions.getVdwFromLevelDiagram (…) 
Finds \(r_{\rm vdW}\) coefficient for original pair state. 
StarkMapResonances Methods
StarkMapResonances.findResonances (nMin, …) 
Finds nearresonant dipolecoupled pairstates 
StarkMapResonances.showPlot ([interactive]) 
Plots initial state Stark map and its dipolecoupled resonances 
Detailed documentation¶
Pairstate basis level diagram calculations
Calculates Rydberg spaghetti of level diagrams, as well as pertubative C6 and similar properties. It also allows calculation of Foster resonances tuned by DC electric fields.
Example
Calculation of the Rydberg eigenstates in pairstate basis for Rubidium in the vicinity of the \(60~S_{1/2}~m_j=1/2,~60~S_{1/2}~m_j=1/2\rangle\) state. Colour highlights coupling strength from state \(6~P_{1/2}~m_j=1/2\) with \(\pi\) (\(q=0\)) polarized light. eigenstates:
from arc import *
calc1 = PairStateInteractions(Rubidium(), 60, 0, 0.5, 60, 0, 0.5,0.5, 0.5)
calc1.defineBasis( 0., 0., 4, 5,10e9)
# optionally we can save now results of calculation for future use
saveCalculation(calc1,"mycalculation.pkl")
calculation1.diagonalise(linspace(1,10.0,30),250,progressOutput = True,drivingFromState=[6,1,0.5,0.5,0])
calc1.plotLevelDiagram()
calc1.ax.set_xlim(1,10)
calc1.ax.set_ylim(2,2)
calc1.showPlot()

class
arc.calculations_atom_pairstate.
PairStateInteractions
(atom, n, l, j, nn, ll, jj, m1, m2, interactionsUpTo=1, s=0.5, s2=None, atom2=None)[source]¶ Calculates Rydberg level diagram (spaghetti) for the given pair state
Initializes Rydberg level spaghetti calculation for the given atom species (or for two atoms of different species) in the vicinity of the given pair state. For details of calculation see Ref. [1]. For a quick start point example see interactions example snippet.
Parameters:  atom (
AlkaliAtom
orDivalentAtom
) – = {arc.alkali_atom_data.Lithium6
,arc.alkali_atom_data.Lithium7
,arc.alkali_atom_data.Sodium
,arc.alkali_atom_data.Potassium39
,arc.alkali_atom_data.Potassium40
,arc.alkali_atom_data.Potassium41
,arc.alkali_atom_data.Rubidium85
,arc.alkali_atom_data.Rubidium87
,arc.alkali_atom_data.Caesium
,arc.divalent_atom_data.Strontium88
,arc.divalent_atom_data.Calcium40
arc.divalent_atom_data.Ytterbium174
} Select the alkali metal for energy level diagram calculation  n (int) – principal quantum number for the first atom
 l (int) – orbital angular momentum for the first atom
 j (float) – total angular momentum for the first atom
 nn (int) – principal quantum number for the second atom
 ll (int) – orbital angular momentum for the second atom
 jj (float) – total angular momentum for the second atom
 m1 (float) – projection of the total angular momentum on zaxis for the first atom
 m2 (float) – projection of the total angular momentum on zaxis for the second atom
 interactionsUpTo (int) – Optional. If set to 1, includes only dipoledipole interactions. If set to 2 includes interactions up to quadrupolequadrupole. Default value is 1.
 s (float) – optional, spin state of the first atom. Default value
of 0.5 is correct for
AlkaliAtom
but forDivalentAtom
it has to be explicitly set to 0 or 1 for singlet and triplet states respectively. If `s2` is not specified, it is assumed that the second atom is in the same spin state.  s2 (float) – optinal, spin state of the second atom. If not specified (left to default value None) it will assume spin state of the first atom.
 atom2 (
AlkaliAtom
orDivalentAtom
) – optional, specifies atomic species for the second atom, enabeling calculation of interspecies pairstate interactions. If not specified (left to default value None) it will assume spin state of the first atom.
References
[1] T. G Walker, M. Saffman, PRA 77, 032723 (2008) https://doi.org/10.1103/PhysRevA.77.032723 Examples
Advanced interfacing of pairstate is2=None, atom2=Nonenteractions calculations (PairStateInteractions class). This is an advanced example intended for building up extensions to the existing code. If you want to directly access the pairstate interaction matrix, constructed by
defineBasis
, you can assemble it easily from diagonal part (stored inmatDiagonal
) and offdiagonal matrices whose spatial dependence is \(R^{3},R^{4},R^{5}\) stored in that order inmatR
. Basis states are stored inbasisStates
array.>>> from arc import * >>> calc = PairStateInteractions(Rubidium(), 60,0,0.5, 60,0,0.5, 0.5,0.5,interactionsUpTo = 1) >>> # theta=0, phi = 0, range of pqn, range of l, deltaE = 25e9 >>> calc.defineBasis(0 ,0 , 5, 5, 25e9, progressOutput=True) >>> # now calc stores interaction matrix and relevant basis >>> # we can access this directly and generate interaction matrix >>> # at distance rval : >>> rval = 4 # in mum >>> matrix = calc.matDiagonal >>> rX = (rval*1.e6)**3 >>> for matRX in self.matR: >>> matrix = matrix + matRX/rX >>> rX *= (rval*1.e6) >>> # matrix variable now holds full interaction matrix for >>> # interacting atoms at distance rval calculated in >>> # pairstate basis states can be accessed as >>> basisStates = calc.basisStates

atom1
= None¶ atom type

basisStates
= None¶ List of pairstates for calculation. In the form [[n1,l1,j1,mj1,n2,l2,j2,mj2], …]. Each state is an array [n1,l1,j1,mj1,n2,l2,j2,mj2] corresponding to \(n_1,l_1,j_1,m_{j1},n_2,l_2,j_2,m_{j2}\rangle\) state. Calculated by
defineBasis
.

channel
= None¶ states relevant for calculation, defined in J basis (not resolving \(m_j\). Used as intermediary for full interaction matrix calculation by
defineBasis
.

coupling
= None¶ List of matrices defineing coupling strengths between the states in J basis (not resolving \(m_j\) ). Basis is given by
channel
. Used as intermediary for full interaction matrix calculation bydefineBasis
.

defineBasis
(theta, phi, nRange, lrange, energyDelta, Bz=0, progressOutput=False, debugOutput=False)[source]¶ Finds relevant states in the vicinity of the given pairstate
Finds relevant pairstate basis and calculates interaction matrix. Pairstate basis is saved in
basisStates
. Interaction matrix is saved in parts depending on the scaling with distance. Diagonal elementsmatDiagonal
, correponding to relative energy defects of the pairstates, don’t change with interatomic separation. Off diagonal elements can depend on distance as \(R^{3}, R^{4}\) or \(R^{5}\), corresponding to dipoledipole (\(C_3\) ), dipolequdrupole (\(C_4\) ) and quadrupolequadrupole coupling (\(C_5\) ) respectively. These parts of the matrix are stored inmatR
in that order. I.e.matR[0]
stores dipoledipole coupling (\(\propto R^{3}\)),matR[0]
stores dipolequadrupole couplings etc.Parameters:  theta (float) – relative orientation of the two atoms (see figure on top of the page), range 0 to \(\pi\)
 phi (float) – relative orientation of the two atoms (see figure on top of the page), range 0 to \(2\pi\)
 nRange (int) – how much below and above the given principal quantum number of the pair state we should be looking?
 lrange (int) – what is the maximum angular orbital momentum state that we are including in calculation
 energyDelta (float) – what is maximum energy difference ( \(\Delta E/h\) in Hz) between the original pair state and the other pair states that we are including in calculation
 Bz (float) – optional, magnetic field directed along zaxis in units of Tesla. Calculation will be correct only for weak magnetic fields, where paramagnetic term is much stronger then diamagnetic term. Diamagnetic term is neglected.
 progressOutput (bool) – optional, False by default. If true, prints information about the progress of the calculation.
 debugOutput (bool) – optional, False by default. If true, similarly to progressOutput=True, this will print information about the progress of calculations, but with more verbose output.
See also
alkali_atom_functions.saveCalculation
andalkali_atom_functions.loadSavedCalculation
for information on saving intermediate results of calculation for later use.

diagonalise
(rangeR, noOfEigenvectors, drivingFromState=[0, 0, 0, 0, 0], eigenstateDetuning=0.0, sortEigenvectors=False, progressOutput=False, debugOutput=False)[source]¶ Finds eigenstates in atom pair basis.
ARPACK (
scipy.sparse.linalg.eigsh
) calculation of the noOfEigenvectors eigenvectors closest to the original state. If drivingFromState is specified as [n,l,j,mj,q] coupling between the pairstates and the situation where one of the atoms in the pair state basis is in \(n,l,j,m_j\rangle\) state due to driving with a laser field that drives \(q\) transition (+1,0,1 for \(\sigma^\), \(\pi\) and \(\sigma^+\) transitions respectively) is calculated and marked by the colourmaping these values on the obtained eigenvectors.Parameters:  rangeR (
array
) – Array of values for distance between the atoms (in \(\mu\) m) for which we want to calculate eigenstates.  noOfEigenvectors (int) – number of eigen vectors closest to the energy of the original (unperturbed) pair state. Has to be smaller then the total number of states.
 eigenstateDetuning (float, optional) – Default is 0. This specifies detuning from the initial pairstate (in Hz) around which we want to find noOfEigenvectors eigenvectors. This is useful when looking only for couple of offresonant features.
 drivingFromState ([int,int,float,float,int]) – Optional. State of one of the atoms from the original pairstate basis from which we try to drive to the excited pairbasis manifold, assuming that the first of the two atoms is already excited to the specified Rydberg state. By default, program will calculate just contribution of the original pairstate in the eigenstates obtained by diagonalization, and will highlight it’s admixure by colour mapping the obtained eigenstates plot. State is specified as \([n,\ell,j,mj, d]\) where \(d\) is +1, 0 or 1 for driving \(\sigma^\) , \(\pi\) and \(\sigma^+\) transitions respectively.
 sortEigenvectors (bool) – optional, False by default. Tries to sort eigenvectors so that given eigen vector index corresponds to adiabatically changing eigenstate, as detirmined by maximising overlap between old and new eigenvectors.
 progressOutput (bool) – optional, False by default. If true, prints information about the progress of the calculation.
 debugOutput (bool) – optional, False by default. If true, similarly to progressOutput=True, this will print information about the progress of calculations, but with more verbose output.
 rangeR (

exportData
(fileBase, exportFormat='csv')[source]¶ Exports PairStateInteractions calculation data.
Only supported format (selected by default) is .csv in a humanreadable form with a header that saves details of calculation. Function saves three files: 1) filebase _r.csv; 2) filebase _energyLevels 3) filebase _highlight
For more details on the format, see header of the saved files.
Parameters:  filebase (string) – filebase for the names of the saved files without format extension. Add as a prefix a directory path if necessary (e.g. saving outside the current working directory)
 exportFormat (string) – optional. Format of the exported file. Currently only .csv is supported but this can be extended in the future.

getC3fromLevelDiagram
(rStart, rStop, showPlot=False, minStateContribution=0.0, resonantBranch=1)[source]¶ Finds \(C_3\) coefficient for original pair state.
Function first finds for each distance in the range [rStart , rStop] the eigen state with highest contribution of the original state. One can set optional parameter minStateContribution to value in the range [0,1), so that function finds only states if they have contribution of the original state that is bigger then minStateContribution.
Once original pairstate is found in the range of interatomic distances, from smallest rStart to the biggest rStop, function will try to perform fitting of the corresponding state energy \(E(R)\) at distance \(R\) to the function \(A+C_3/R^3\) where \(A\) is some offset.
Parameters:  rStart (float) – smallest interatomic distance to be used for fitting
 rStop (float) – maximum interatomic distance to be used for fitting
 showPlot (bool) – If set to true, it will print the plot showing fitted energy level and the obtained best fit. Default is False
 minStateContribution (float) – valid values are in the range [0,1). It specifies minimum amount of the original state in the given energy state necessary for the state to be considered for the adiabatic continuation of the original unperturbed pair state.
 resonantBranch (int) – optional, default +1. For resonant interactions we have two branches with identical state contributions. In this case, we will select only positively detuned branch (for resonantBranch = +1) or negatively detuned branch (fore resonantBranch = 1) depending on the value of resonantBranch optional parameter
Returns: \(C_3\) measured in \(\text{GHz }\mu\text{m}^6\) on success; If unsuccessful returns False.
Return type: Note
In order to use this functions, highlighting in
diagonalise
should be based on the original pair state contribution of the eigenvectors (that this, drivingFromState parameter should not be set, which corresponds to drivingFromState = [0,0,0,0,0]).

getC6fromLevelDiagram
(rStart, rStop, showPlot=False, minStateContribution=0.0)[source]¶ Finds \(C_6\) coefficient for original pair state.
Function first finds for each distance in the range [ rStart , rStop ] the eigen state with highest contribution of the original state. One can set optional parameter minStateContribution to value in the range [0,1), so that function finds only states if they have contribution of the original state that is bigger then minStateContribution.
Once original pairstate is found in the range of interatomic distances, from smallest rStart to the biggest rStop, function will try to perform fitting of the corresponding state energy \(E(R)\) at distance \(R\) to the function \(A+C_6/R^6\) where \(A\) is some offset.
Parameters:  rStart (float) – smallest interatomic distance to be used for fitting
 rStop (float) – maximum interatomic distance to be used for fitting
 showPlot (bool) – If set to true, it will print the plot showing fitted energy level and the obtained best fit. Default is False
 minStateContribution (float) – valid values are in the range [0,1). It specifies minimum amount of the original state in the given energy state necessary for the state to be considered for the adiabatic continuation of the original unperturbed pair state.
Returns: \(C_6\) measured in \(\text{GHz }\mu\text{m}^6\) on success; If unsuccessful returns False.
Return type: Note
In order to use this functions, highlighting in
diagonalise
should be based on the original pair state contribution of the eigenvectors (that this, drivingFromState parameter should not be set, which corresponds to drivingFromState = [0,0,0,0,0]).

getC6perturbatively
(theta, phi, nRange, energyDelta, degeneratePerturbation=False)[source]¶ Calculates \(C_6\) from second order perturbation theory.
Calculates \(C_6=\sum_{\rm r',r''}\langle {\rm r',r''}V\ {\rm r1,r2}\rangle^2/\Delta_{\rm r',r''}\), where \(\Delta_{\rm r',r''}\equiv E({\rm r',r''})E({\rm r1, r2})\) When second order perturbation couples to multiple energy degenerate states, users shold use degenerate perturbation calculations by setting degeneratePerturbation=True .
This calculation is faster then full diagonalization, but it is valid only far from the so called spaghetti region that occurs when atoms are close to each other. In that region multiple levels are strongly coupled, and one needs to use full diagonalization. In region where perturbative calculation is correct, energy level shift can be obtained as \(V(R)=C_6/R^6\)
See perturbative C6 calculations example snippet.
Parameters:  theta (float) – orientation of interatomic axis with respect to quantization axis (\(z\)) in Euler coordinates (measured in units of radian)
 phi (float) – orientation of interatomic axis with respect to quantization axis (\(z\)) in Euler coordinates (measured in units of radian)
 nRange (int) – how much below and above the given principal quantum number of the pair state we should be looking
 energyDelta (float) – what is maximum energy difference ( \(\Delta E/h\) in Hz) between the original pair state and the other pair states that we are including in calculation
 degeneratePerturbation (bool) – optional, default False. Should one use degenerate perturbation theory. This should be used whenever angle between quantisation and interatomic axis is nonzero, as well as when one considers nonstretched states.
Returns: if degeneratePerturbation=False, returns \(C_6\) measured in \(\text{GHz }\mu\text{m}^6\); if degeneratePerturbation=True, returns array of \(C_6\) measured in \(\text{GHz }\mu\text{m}^6\) AND array of corresponding eigenvectors in \(\{m_{j_1}=j_1, \ldots, m_{j_1} = +j1\}\bigotimes \ \{ m_{j_2}=j_2, \ldots, m_{j_2} = +j2\}\) basis
Return type: Example
If we want to quickly calculate \(C_6\) for two Rubidium atoms in state \(62 D_{3/2} m_j=3/2\), positioned in space along the shared quantization axis:
from arc import * calculation = PairStateInteractions(Rubidium(), 62, 2, 1.5, 62, 2, 1.5, 1.5, 1.5) c6 = calculation.getC6perturbatively(0,0, 5, 25e9) print "C_6 = %.0f GHz (mu m)^6" % c6
Which returns:
C_6 = 767 GHz (mu m)^6
Quick calculation of angular anisotropy of for Rubidium \(D_{2/5},m_j=5/2\) states:
# Rb 60 D_{2/5}, mj=2.5 , 60 D_{2/5}, mj=2.5 pair state calculation1 = PairStateInteractions(Rubidium(), 60, 2, 2.5, 60, 2, 2.5, 2.5, 2.5) # list of atom orientations thetaList = np.linspace(0,pi,30) # do calculation of C6 pertubatively for all atom orientations c6 = [] for theta in thetaList: value = calculation1.getC6perturbatively(theta,0,5,25e9) c6.append(value) print ("theta = %.2f * pi \tC6 = %.2f GHz mum^6" % (theta/pi,value)) # plot results plot(thetaList/pi,c6,"b") title("Rb, pairstate 60 $D_{5/2},m_j = 5/2$, 60 $D_{5/2},m_j = 5/2$") xlabel(r"$\Theta /\pi$") ylabel(r"$C_6$ (GHz $\mu$m${}^6$") show()

getLeRoyRadius
()[source]¶ Returns Le Roy radius for initial pairstate.
Le Roy radius [2] is defined as \(2(\langle r_1^2 \rangle^{1/2} + \langle r_2^2 \rangle^{1/2})\), where \(r_1\) and \(r_2\) are electron coordinates for the first and the second atom in the initial pairstate. Below this radius, calculations are not valid since electron wavefunctions start to overlap.
Returns: LeRoy radius measured in \(\mu m\) Return type: float References
[2] R.J. Le Roy, Can. J. Phys. 52, 246 (1974) http://www.nrcresearchpress.com/doi/abs/10.1139/p74035

getVdwFromLevelDiagram
(rStart, rStop, showPlot=False, minStateContribution=0.0)[source]¶ Finds \(r_{\rm vdW}\) coefficient for original pair state.
Function first finds for each distance in the range [rStart,`rStop`] the eigen state with highest contribution of the original state. One can set optional parameter minStateContribution to value in the range [0,1), so that function finds only states if they have contribution of the original state that is bigger then minStateContribution.
Once original pairstate is found in the range of interatomic distances, from smallest rStart to the biggest rStop, function will try to perform fitting of the corresponding state energy \(E(R)\) at distance \(R\) to the function \(A+B\frac{1\sqrt{1+(r_{\rm vdW}/r)^6}}{1\sqrt{1+r_{\rm vdW}^6}}\)
where \(A\) and \(B\) are some offset.Parameters:  rStart (float) – smallest interatomic distance to be used for fitting
 rStop (float) – maximum interatomic distance to be used for fitting
 showPlot (bool) – If set to true, it will print the plot showing fitted energy level and the obtained best fit. Default is False
 minStateContribution (float) – valid values are in the range [0,1). It specifies minimum amount of the original state in the given energy state necessary for the state to be considered for the adiabatic continuation of the original unperturbed pair state.
Returns: \(r_{\rm vdW}\) measured in \(\mu\text{m}\) on success; If unsuccessful returns False.
Return type: Note
In order to use this functions, highlighting in
diagonalise
should be based on the original pair state contribution of the eigenvectors (that this, drivingFromState parameter should not be set, which corresponds to drivingFromState = [0,0,0,0,0]).

interactionsUpTo
= None¶ ” Specifies up to which approximation we include in pairstate interactions. By default value is 1, corresponding to pairstate interactions up to dipoledipole coupling. Value of 2 is also supported, corresponding to pairstate interactions up to quadrupolequadrupole coupling.

matDiagonal
= None¶ Part of interaction matrix in pairstate basis that doesn’t depend on interatomic distance. E.g. diagonal elements of the interaction matrix, that describe energies of the pair states in unperturbed basis, will be stored here. Basis states are stored in
basisStates
. Calculated bydefineBasis
.

matR
= None¶ Stores interaction matrices in pairstate basis that scale as \(1/R^3\), \(1/R^4\) and \(1/R^5\) with distance in
matR[0]
,matR[1]
andmatR[2]
respectively. These matrices correspond to dipoledipole ( \(C_3\)), dipolequadrupole ( \(C_4\)) and quadrupolequadrupole ( \(C_5\)) interactions coefficients. Basis states are stored inbasisStates
. Calculated bydefineBasis
.

matrixElement
= None¶ matrixElement[i] gives index of state in
channel
basis (that doesn’t resolvem_j
states), for the given index i of the state inbasisStates
( \(m_j\) resolving) basis.

originalPairStateIndex
= None¶ index of the original n,l,j,m1,nn,ll,jj,m2 pairstate in the
basisStates
basis.

plotLevelDiagram
(highlightColor='red', highlightScale='linear')[source]¶ Plots pair state level diagram
Call
showPlot
if you want to display a plot afterwards.Parameters:  highlightColor (string) – optional, specifies the colour used for state highlighting
 highlightScale (string) – optional, specifies scaling of state highlighting. Default is ‘linear’. Use ‘log2’ or ‘log3’ for logarithmic scale going down to 1e2 and 1e3 respectively. Logarithmic scale is useful for spotting weakly admixed states.

s1
= None¶ total spin angular momentum, optional (default 0.5)

savePlot
(filename='PairStateInteractions.pdf')[source]¶ Saves plot made by
plotLevelDiagram
Parameters: filename ( str
, optional) – file location where the plot should be saved

showPlot
(interactive=True)[source]¶ Shows level diagram printed by
PairStateInteractions.plotLevelDiagram
By default, it will output interactive plot, which means that clicking on the state will show the composition of the clicked state in original basis (dominant elements)
Parameters: interactive (bool) – optional, by default it is True. If true, plotted graph will be interactive, i.e. users can click on the state to identify the state composition Note
interactive=True has effect if the graphs are explored in usual matplotlib popup windows. It doesn’t have effect on inline plots in Jupyter (IPython) notebooks.
 atom (

class
arc.calculations_atom_pairstate.
StarkMapResonances
(atom1, state1, atom2, state2)[source]¶ Calculates pair state Stark maps for finding resonances
Tool for finding conditions for Foster resonances. For a given pair state, in a given range of the electric fields, looks for the pairstate that are close in energy and coupled via dipoledipole interactions to the original pairstate.
See Stark resonances example snippet.
Parameters:  atom (
AlkaliAtom
) –={
alkali_atom_data.Lithium6
,alkali_atom_data.Lithium7
,alkali_atom_data.Sodium
,alkali_atom_data.Potassium39
,alkali_atom_data.Potassium40
,alkali_atom_data.Potassium41
,alkali_atom_data.Rubidium85
,alkali_atom_data.Rubidium87
,alkali_atom_data.Caesium
}the first atom in the pairstate  state1 ([int,int,float,float,(float)]) – specification of the state of the first state as an array of values \([n,l,j,m_j]\). For obj:DivalentAtom and other divalent atoms, 5th value should be added specifying total spin angular momentum s. Full definition of state then has format \([n,l,j,m_j,s]\).
 atom –
={
alkali_atom_data.Lithium6
,alkali_atom_data.Lithium7
,alkali_atom_data.Sodium
,alkali_atom_data.Potassium39
,alkali_atom_data.Potassium40
,alkali_atom_data.Potassium41
,alkali_atom_data.Rubidium85
,alkali_atom_data.Rubidium87
,alkali_atom_data.Caesium
}the second atom in the pairstate  state2 ([int,int,float,float,(float)]) – specification of the state of the first state as an array of values \([n,l,j,m_j]\), For obj:DivalentAtom and other divalent atoms, 5th value should be added specifying total spin angular momentum s. Full definition of state then has format \([n,l,j,m_j,s]\).
Note
In checking if certain state is dipole coupled to the original state, only the highest contributing state is checked for dipole coupling. This should be fine if one is interested in resonances in weak fields. For stronger fields, one might want to include effect of coupling to other contributing base states.

findResonances
(nMin, nMax, maxL, eFieldList, energyRange=[5000000000.0, 5000000000.0], Bz=0, progressOutput=False)[source]¶ Finds nearresonant dipolecoupled pairstates
For states in range of principal quantum numbers [nMin,`nMax`] and orbital angular momentum [0,`maxL`], for a range of electric fields given by eFieldList function will find nearresonant pair states.
Only states that are in the range given by energyRange will be extracted from the pairstate Stark maps.
Parameters:  nMin (int) – minimal principal quantum number of the state to be included in the StarkMap calculation
 nMax (int) – maximal principal quantum number of the state to be included in the StarkMap calculation
 maxL (int) – maximum value of orbital angular momentum for the states to be included in the calculation
 eFieldList ([float]) – list of the electric fields (in V/m) for which to calculate level diagram (StarkMap)
 Bz (float) – optional, magnetic field directed along zaxis in units of Tesla. Calculation will be correct only for weak magnetic fields, where paramagnetic term is much stronger then diamagnetic term. Diamagnetic term is neglected.
 energyRange ([float,float]) – optinal argument. Minimal and maximal energy of that some dipolecoupled state should have in order to keep it in the plot (in units of Hz). By default it finds states that are \(\pm 5\) GHz
 progressOutput (
bool
, optional) – if True prints the progress of calculation; Set to false by default.

showPlot
(interactive=True)[source]¶ Plots initial state Stark map and its dipolecoupled resonances
Parameters: interactive (optional, bool) – if True (by default) points on plot will be clickable so that one can find the state labels and their composition (if they are heavily admixed). Note
Zero is given by the initial states of the atom given in initialisation of calculations, calculated in absence of magnetic field B_z. In other words, for nonzero magnetic field the inital states will have offset from zero even for zero electric field due to Zeeman shift.
 atom (