Linear response in velocity gauge - Revision history

Davide: removed new line commands

2025-05-26T10:23:22Z

removed new line commands

← Older revision		Revision as of 10:23, 26 May 2025
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	[[File:Lresp.png\|thumb\|200px]]		[[File:Lresp.png\|thumb\|200px]]
	In this tutorial we show how to get the linear response using the velocity gauge~~<br>~~ instead of the Berry phase approach in length gauge.<br>		In this tutorial we show how to get the linear response using the velocity gauge instead of the Berry phase approach in length gauge.<br>
	We use the same DFT input files of the tutorial [[Linear response using Dynamical Berry Phase]], ~~<br>~~run the same setup and remove the symmetries.		We use the same DFT input files of the tutorial [[Linear response using Dynamical Berry Phase]], run the same setup and remove the symmetries.
	<br>		<br>
	== Real-time dynamics in velocity gauge==		== Real-time dynamics in velocity gauge==

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-14T10:09:12Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 10:09, 14 November 2023
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	pol=-pol		pol=-pol

	~~Plot_Pol~~(time=time, pol=pol, xlim=[0,55], save_file='polarization.pdf')		Plot_Pol_or_Curr(time=time, pol=pol, xlim=[0,55], save_file='polarization.pdf')
	#		#
	pol_damped=np.empty_like(pol)		pol_damped=np.empty_like(pol)

Attacc: /* Analysis of the results using YamboPy using polarization */

2023-11-14T10:08:54Z

Analysis of the results using YamboPy using polarization

← Older revision		Revision as of 10:08, 14 November 2023
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	pol_damped[i_d,:]=damp_it(pol[i_d,:],time,t_initial,damp_type='LORENTZIAN',damp_factor=0.1/ha2ev)		pol_damped[i_d,:]=damp_it(pol[i_d,:],time,t_initial,damp_type='LORENTZIAN',damp_factor=0.1/ha2ev)

	~~Plot_Pol~~(time=time, pol=pol_damped, xlim=[0,55], save_file='polarization.pdf')		Plot_Pol_or_Curr(time=time, pol=pol_damped, xlim=[0,55], save_file='polarization.pdf')

	[[File:Polarization velocity.png\|center\|Polarization_velocity]]		[[File:Polarization velocity.png\|center\|Polarization_velocity]]

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:38:16Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:38, 7 November 2023
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	[[File:Eps vel.png\|center\|Yambo tutorial image]]		[[File:Eps vel.png\|center\|Yambo tutorial image]]

	This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it (see Ref. <ref>Manipulation of the dielectric properties of diamond by an ultrashort laser pulse, X. Zhang, F. Wang, L. Jiang, and Y. Yao Phys. Rev. '''B''' 95, 184301</ref>)		This procedure produce a small bump at <math>\omega=0</math> that is an artifact, different procedure has been discussed in the literature to remove it (see Ref. <ref>Manipulation of the dielectric properties of diamond by an ultrashort laser pulse, X. Zhang, F. Wang, L. Jiang, and Y. Yao Phys. Rev. '''B''' 95, 184301</ref>)

	== References==		== References==

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:32:41Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:32, 7 November 2023
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	#		#
	Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )		Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )

			and you the get the spectra:

			[[File:Eps vel.png\|center\|Yambo tutorial image]]

	This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it (see Ref. <ref>Manipulation of the dielectric properties of diamond by an ultrashort laser pulse, X. Zhang, F. Wang, L. Jiang, and Y. Yao Phys. Rev. '''B''' 95, 184301</ref>)		This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it (see Ref. <ref>Manipulation of the dielectric properties of diamond by an ultrashort laser pulse, X. Zhang, F. Wang, L. Jiang, and Y. Yao Phys. Rev. '''B''' 95, 184301</ref>)

	== References==		== References==

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:27:30Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:27, 7 November 2023
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	Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )		Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )

	This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it.		This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it (see Ref. <ref>Manipulation of the dielectric properties of diamond by an ultrashort laser pulse, X. Zhang, F. Wang, L. Jiang, and Y. Yao Phys. Rev. '''B''' 95, 184301</ref>)

	== References==		== References==

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:22:13Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:22, 7 November 2023
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	==Analysis of the results using YamboPy using current ==		==Analysis of the results using YamboPy using current ==

	The same analysis can be performed using the current. In this case we remove the constant term then we reconstruct the polarization		The same analysis can be performed using the current. <br>In this case we remove the constant term then we reconstruct the polarization
	and then the epsilon~~. This procedure produce a small bump at \omega=0 that is an artifact~~.		and then the epsilon.

	import numpy as np		import numpy as np
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	#		#
	Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )		Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )

			This procedure produce a small bump at \omega=0 that is an artifact, different procedure has been discussed in the literature to remove it.

			== References==

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:18:14Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:18, 7 November 2023
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	from scipy.interpolate import CubicSpline		from scipy.interpolate import CubicSpline
	import matplotlib.pyplot as plt		import matplotlib.pyplot as plt

	NLDB=YamboNLDB()		NLDB=YamboNLDB()

	current =NLDB.Current[0]		current =NLDB.Current[0]
	time=NLDB.IO_TIME_points		time=NLDB.IO_TIME_points

Attacc: /* Analysis of the results using YamboPy using current */

2023-11-07T14:18:06Z

Analysis of the results using YamboPy using current

← Older revision		Revision as of 14:18, 7 November 2023
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	==Analysis of the results using YamboPy using current ==		==Analysis of the results using YamboPy using current ==

			The same analysis can be performed using the current. In this case we remove the constant term then we reconstruct the polarization
			and then the epsilon. This procedure produce a small bump at \omega=0 that is an artifact.

			import numpy as np
			from yambopy import *
			from yambopy.plot import *
			from scipy.interpolate import CubicSpline
			import matplotlib.pyplot as plt

			NLDB=YamboNLDB()

			current =NLDB.Current[0]
			time=NLDB.IO_TIME_points
			t_initial=NLDB.Efield[0]["initial_time"]
			#
			# Remove the constant term
			#
			ave_current=np.zeros(3,dtype=np.double)
			for i_d in range(3):
			ave_current[i_d]=np.sum(current[i_d,:])/current.shape[1]
			current[i_d,:]=current[i_d,:]-ave_current[i_d]

			pol=np.empty_like(current)
			for i_d in range(3):
			spline_j=CubicSpline(time,current[i_d,:])
			for idx, t in enumerate(time):
			pol[i_d,idx]=spline_j.integrate(0.0,t)

			#
			# There is a wrong sign convention in the velocity gauge
			# somewhere in the code
			#
			pol=-pol

			Plot_Pol(time=time, pol=pol, xlim=[0,55], save_file='polarization.pdf')
			#
			pol_damped=np.empty_like(pol)
			for i_d in range(3):
			pol_damped[i_d,:]=damp_it(pol[i_d,:],time,t_initial,damp_type='LORENTZIAN',damp_factor=0.1/ha2ev)
			#
			#
			# Calculate the linear response
			#
			Linear_Response(time=time,pol=pol_damped,efield=NLDB.Efield[0],plot=False,plot_file='eps.pdf' )

Attacc: /* Analysis of the results using YamboPy using polarization */

2023-11-07T10:02:27Z

Analysis of the results using YamboPy using polarization

← Older revision		Revision as of 10:02, 7 November 2023
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	==Analysis of the results using YamboPy using polarization ==		==Analysis of the results using YamboPy using polarization ==
	'''This part works only with Yambo 5.3 or the last version available on Github:''' [https://github.com/yambo-code/yambo https://github.com/yambo-code/yambo]		'''This part works only with Yambo 5.3 or the last version available on Github:''' [https://github.com/yambo-code/yambo https://github.com/yambo-code/yambo]<br>
	You can get the dielectric constant along the field direction using the same procedure of the Berry Phase case, Fourier transforming the polarization:		You can get the dielectric constant along the field direction using the same procedure of the Berry Phase case, Fourier transforming the polarization: