We are part of the condensed matter theory group in the school of physical sciences at NISER, India.  Broadly speaking, we are interested in understanding how multiple degrees of freedom behave collectively under the rules of quantum mechanics.


News
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  • Postdoc positions are available !! (Click here for details)
  • Paper on disorder driven non Fermi liquid to appear in Phys. Rev. Lett.  (Aug, 2017)
  • Siddhartha Shankar Dash (Master's student in our group) joining University of Sherbrooke for PhD, Fall 17

Current interests include:


Non Fermi liquids, metallic spin/charge glass states: 


We have recently shown that a non Fermi Liquid behaviour is supported by a metal that arises form a competition between interactions and disorder. While that is not surprising in itself, it appears that by varying the interaction strength and disorder strength, the transport exponent of scaling of resistivity with temperature can be tuned. We are currently investigating the universality of such tunability in NFL states in general, its dependence on nature of disorder, relations to QCP's, glassy precursors and finally material systematics of tunable as seen, for example, in heavy fermion systems.


Multi-band correlated materials: 


One of our major interest lies in understanding the interplay of Coulomb correlation and bandwidth in presence of large orbital degeneracy. Orbital selective Mott transition in the Pnictides, strong transition metal-oxygen covalency in small or negative charge transfer transition metal oxides (TMO) are typical examples where theoretical modeling needs to retain the multi-orbital nature of the material. Thus a major challenge is to solve realistic multi-band Hubbard like Hamiltonians at zero and finite temperature. We continue using a combination of mean field and exact tools to investigate a number of problems in this area. 


Few body Green’s functions: 


Few-particle bound states are relevant in the interpretation of certain spectroscopic data. The role played by bound two-particle states, leading to atomic like multiplet structures in the Auger spectra of narrow band insulating oxides, is well established. Auger electron spectra is a measure of the two hole local density of states and contains information on the d-p hybridization when such measurement is performed for TMOs. In this respect it ties up with our above mentioned interest in negative charge transfer oxides. We have recently developed a new variational approach, using a continued fraction representation of lattice Green’s functions, that allows accurate evaluation of few body spectral functions. Our aim is to apply the method for calculating Auger spectra for correlated materials. We are also interested in applying the method to studying the stability of few particle excitations in low dimensional systems and cold atom traps. 



Contact: 

National Institute of Science Education and Research 

Bhubaneswar P.O. Jatni, Khurda 752050, Odisha, India. 

Phone: +912494280; Email: anamitra.AT.niser.ac.in