# Shailesh Chandrasekharan

### **Professor of Physics**

### Overview

Prof. Chandrasekharan is interested in understanding quantum field theories non-perturbatively from first principles calculations. His research focuses on lattice formulations of these theories with emphasis on strongly correlated fermionic systems of interest in condensed matter, particle and nuclear physics. He develops novel Monte-Carlo algorithms to study these problems. He is particularly excited about solutions to the notoriously difficult sign problem that haunts quantum systems containing fermions and gauge fields. He has proposed an idea called the fermion bag approach, using which he has been able to solve numerous sign problems that seemed unsolvable earlier. Using various algorithmic advances over the past decade, he is interested in understanding the properties of quantum critical points containing interacting fermions. Some of his recent publications can be found here. Recently he is exploring how one can use quantum computers to solve quantum field theories.

### Selected Grants

Lattice and Effective Field Theory Studies of Quantum Chromodynamics awarded by Department of Energy (Co-Principal Investigator). 2005 to 2021

Quantum Field Theory as Spin Models on Quantum Computers awarded by Los Alamos National Laboratory (Principal Investigator). 2019 to 2020

Coherence and Correlations in Electronic Nanostructures awarded by National Science Foundation (Co-Principal Investigator). 2005 to 2009

Coherence and Correlation in Electronic Nanostructures awarded by National Science Foundation (Co-Principal Investigator). 2001 to 2006

Toward the Chiral Limit in QCD awarded by Department of Energy (Principal Investigator). 2003 to 2005

Quantum Chromodynamics and Nuclear Physics at Extreme Energy Density awarded by Department of Energy (Co-Principal Investigator). 1995 to 2005

Frank, J., et al. “Emergence of Gauss' law in a Z2 lattice gauge theory in 1 + 1 dimensions.” *Physics Letters, Section B: Nuclear, Elementary Particle and High Energy Physics*, vol. 806, July 2020. *Scopus*, doi:10.1016/j.physletb.2020.135484.
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Huffman, E., and S. Chandrasekharan. “Fermion-bag inspired Hamiltonian lattice field theory for fermionic quantum criticality.” *Physical Review D*, vol. 101, no. 7, Apr. 2020. *Scopus*, doi:10.1103/PhysRevD.101.074501.
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Singh, H., and S. Chandrasekharan. “Qubit regularization of the O (3) sigma model.” *Physical Review D*, vol. 100, no. 5, Sept. 2019. *Scopus*, doi:10.1103/PhysRevD.100.054505.
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Banerjee, Debasish, et al. “Conformal Dimensions in the Large Charge Sectors at the O(4) Wilson-Fisher Fixed Point.” *Physical Review Letters*, vol. 123, no. 5, Aug. 2019, p. 051603. *Epmc*, doi:10.1103/physrevlett.123.051603.
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Singh, H., and S. Chandrasekharan. “Few-body physics on a spacetime lattice in the worldline approach.” *Physical Review D*, vol. 99, no. 7, Apr. 2019. *Scopus*, doi:10.1103/PhysRevD.99.074511.
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Banerjee, Debasish, et al. “Conformal Dimensions via Large Charge Expansion.” *Physical Review Letters*, vol. 120, no. 6, Feb. 2018, p. 061603. *Epmc*, doi:10.1103/physrevlett.120.061603.
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Ayyar, V., and S. Chandrasekharan. “Generating a nonperturbative mass gap using Feynman diagrams in an asymptotically free theory.” *Physical Review D*, vol. 96, no. 11, Dec. 2017. *Scopus*, doi:10.1103/PhysRevD.96.114506.
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Huffman, E., and S. Chandrasekharan. “Fermion bag approach to Hamiltonian lattice field theories in continuous time.” *Physical Review D*, vol. 96, no. 11, Dec. 2017. *Scopus*, doi:10.1103/PhysRevD.96.114502.
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Hann, C. T., et al. “Solution to the sign problem in a frustrated quantum impurity model.” *Annals of Physics*, vol. 376, Jan. 2017, pp. 63–75. *Scopus*, doi:10.1016/j.aop.2016.11.006.
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Huffman, Emilie, and Shailesh Chandrasekharan. “Solution to sign problems in models of interacting fermions and quantum spins.” *Physical Review. E*, vol. 94, no. 4–1, Oct. 2016, p. 043311. *Epmc*, doi:10.1103/physreve.94.043311.
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## Pages

Chandrasekharan, Shailesh, et al. *Baryon bag simulation of QCD in the strong coupling limit*. arXiv.org, 2019.
Open Access Copy

Ayyar, V., and S. Chandrasekharan. “Generating a mass gap using Feynman diagrams in an asymptotically free theory.” *Epj Web of Conferences*, vol. 175, 2018. *Scopus*, doi:10.1051/epjconf/201817511010.
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Singh, H., and S. Chandrasekharan. “Worldline approach to few-body physics on the Lattice.” *Proceedings of Science*, vol. 334, 2018.

Chandrasekharan, S. “Fermion bags, topology and index theorems.” *Proceedings of Science*, vol. Part F128557, 2016.

Chandrasekharan, S. “Quantum critical behavior with massless staggered fermions in three dimensions.” *Proceedings of Science*, vol. 29-July-2013, 2013.

Cecile, D. J., and S. Chandrasekharan. “-Resonance and convergence of chiral perturbation theory.” *Proceedings of Science*, vol. 66, 2008.

Chandrasekharan, Shailesh, et al. *Emergence of Gauss' Law in a 2 Lattice Gauge Theory*. arXiv.org, 10 Apr. 2019.