1DGEM2L.xmds

<simulation xmds-version="2">
	<name>1DGEM2L</name>
	<author>Anthony</author>
	<description> 2 level gradient echo memory simulation. Solves the 2 level Maxwell-Bloch equations for an ensemble under a classical control field and a weak probe</description>
<features>
	<benchmark />
	<bing />
	<globals>
		<![CDATA[
		const double pi = M_PI;
		double agamma = pi*5.75; 		/* excited state coherence decay (half the excited state linewidth, all frequencies in MHz*/
		const double od = 300;     		/*optical depth*/ 
		const double delta = 2*pi*250;  		/* one-photon detuning*/
		double omega;		/*control field rabi frequency*/
		double eta;   		/*operator for gradient*/

		real gradientswitch(double time){
  if (time < 40) { return 1.0; }
  else {return -1.0; }}

		double gaussian( double x, double w ) { return exp( -2 * pow(x,2) / pow(w,2) ); }
		]]>
	</globals>
	<arguments append_args_to_output_filename="no">
		<argument default_value= "2.5" name = "tin" type = "real" />
		<argument default_value= "2" name = "pulsewidth" type = "real" />
		<argument default_value= "0.1" name = "bandwidth" type = "real" />
		<argument default_value= "5" name = "omega_in" type = "real" />
		<![CDATA[
		omega = 2*pi*omega_in;
		]]>
	</arguments>
</features>
<geometry>
	<propagation_dimension>t</propagation_dimension>
		<transverse_dimensions>
		<dimension domain="(-0.5, 0.5)" lattice="100" name="z" />
		</transverse_dimensions>
</geometry>

<vector initial_space="z" name="spinwave" type="complex">
	<components>S</components>
</vector>

<vector initial_space="z" name="probe" type="complex">
	<components>E</components>
</vector>

<sequence>
	<integrate algorithm="ARK45" interval="80" steps="200" tolerance="1.0e-6">
	<samples>200</samples>
	
	<operators>   
		<operator kind="functions">
		<![CDATA[
		eta = 2*pi*bandwidth * gradientswitch(t); /* placing within the operators simplifies time dependence easier and omits it from the often long Maxwell-Bloch eqs*/
		]]>
		</operator>
				     
		<operator algorithm="RK4" kind="cross_propagation" propagation_dimension="z">
			<integration_vectors> probe </integration_vectors>
			<dependencies>spinwave</dependencies>
			<boundary_condition kind="left">
				<![CDATA[
				E= gaussian(t-tin,pulsewidth);
				]]>
			</boundary_condition>
			<![CDATA[
			dE_dz = i * sqrt(od) * omega * S / delta;
			]]>
		</operator>

			<integration_vectors>spinwave</integration_vectors>
				<![CDATA[
				dS_dt = i * (eta * z * S + sqrt(od) * agamma * omega * E / delta);
			]]>
	</operators>
	</integrate>
</sequence>

<output filename="1DGEM2L" format="hdf5">
	<group>
	<sampling basis="z" initial_sample="yes">
		<moments>SR SI ER EI</moments>
		<dependencies>probe spinwave</dependencies>
		<![CDATA[
		_SAMPLE_COMPLEX(S);
		_SAMPLE_COMPLEX(E);
		]]>
	</sampling>
	</group>
</output>
</simulation>