Molecule Detection (EIT)

The python code with QuTiP package for the simulation of the interaction between cold molecule and two resonator modes in the paper Resonator-assisted single-molecule quantum state detection (PhysRevA.102.023716), which proposes a protocol to detect molecular quantum state with electromagnetically-induced transparency (EIT).

Usage

util.molSystem(duration, spacing, cooperativity, kappa_i, kappa_e, gamma=12, delta_al=0,  delta_cl=0, f_fc=0.37, P_in=1, N_p=3, N_s=3, N_m=1, save=True, save_path="../data/" + strftime("%Y%m%d_%H%M%S", localtime()) + "/", ))

A class to describe the interaction between molecule and resonator modes

Parameters

duration: simulation time (unit: μs)
spacing: spacing of the sample points during simulation
cooperativity: dimensionless cooperativity parameter in cavity QED
kappa_i: intrinsic resonator loss rate (unit: MHz)
kappa_e: coupling rate between waveguide and resonator (unit: MHz)
gamma: excited molecule spontaneous decay rate (unit: MHz)
delta_al: frequency difference between atomic transition and light frequency (unit: MHz)
delta_cl: frequency difference between cavity resonance and light frequency (unit: MHz)
f_fc: Franck-Condon factor P_in: Photon number generation rate at the input side of waveguide N_p: maximum photon number in Fock state N_s: number of molecule states: |0>: |g>; |1>:|e>; |2>:|s> N_m: initial number of molecules
save: if save == False, disable all saving data option save_path: the path to save data. Default value (on linux): "../data/localtime"

Methods

simulation(self, show_progress=None, save_info=True, save_data=False): calculate the Lindbladian master equation. show_progress(None/True) determines whether to show progress bar of calculation.; save_info determines whether to write system parameters into a txt file; save_data determines whether to save the simulation result into the save_path (same as below).
photon_simulated(self, save_data=False): Use simulation result to calculate real-time transmission and reflection as well as the transmitted and reflected photon number as a function of time
photon_theory(self, save_data=False): Use analytical solution to calculate real-time transmission and reflection as well as the transmitted and reflected photon number as a function of time
draw_population(self): draw the graph of molecular state population evolution
draw_comparison_tran(self): draw the real-time transmission curve with the data from simulation and analytical solution. (Used for calibration)

util.tran_spectrum(Mol, delta_max, delta_step, sampletlist, method, calculation="parallel", save_data=False)

a function to calculate the average transmission spectrum and draw a graph of transmission spectrum

Parameters

Mol: an instance of molSystem to provide background parameters (expect detuning)
delta_max: maximum detuning frequency (unit: MHz) delta_step: the increasing step of detuning frequency from zero (unit: MHz) sampletlist: a list of sampling time points to calculate average transmission
method: 'theory' or 'simulation'. Select the method to derive transmission. Default value: 'theory'
calculation: 'serial' or 'parallel'. Select serial or parallel computation. Default value: 'parallel'
save_data: determines whether to save the raw data into the Mol._path.

Examples

from util import molSystem, tran_spectrum

Mol = molSystem(duration=201, spacing=0.01, cooperativity=50, kappa_i=50, kappa_e=50)

Mol.simulation(show_progress=True, save_data=True)
Mol.photon_simulated(save_data=True)
Mol.photon_theory(save_data=True)
Mol.draw_population()
Mol.draw_comparison_tran()

tran_spectrum(
    Mol,
    delta_max=1000,
    delta_step=10,
    sampletlist=[20, 100, 200],
    method="theory",
    calculation="parallel",
    save_data=True,
)

del Mol