Publications

2023

• Dynamical mean-field theory for the Hubbard-Holstein model on a quantum device
  
  • Backes Steffen
  • Murakami Yuta
  • Sakai Shiro
  • Arita Ryotaro
  Physical Review B, American Physical Society, 2023, 107 (16), pp.165155. Recent developments in quantum hardware and quantum algorithms have made it possible to utilize the capabilities of current noisy intermediate-scale quantum devices for addressing problems in quantum chemistry and condensed matter physics. Here we report a demonstration of solving the dynamical mean-field theory (DMFT) impurity problem for the Hubbard-Holstein model on the IBM 27-qubit Quantum Falcon Processor Kawasaki, including self-consistency of the DMFT equations. This opens up the possibility to investigate strongly correlated electron systems coupled to bosonic degrees of freedom and impurity problems with frequency-dependent interactions. The problem involves both fermionic and bosonic degrees of freedom to be encoded on the quantum device, which we solve using a recently proposed Krylov variational quantum algorithm to obtain the impurity Green's function. We find the resulting spectral function to be in good agreement with the exact result, exhibiting both correlation and plasmonic satellites and significantly surpassing the accuracy of standard Trotter-expansion approaches. Our results provide an essential building block to study electronic correlations and plasmonic excitations on future quantum computers with modern ab initio techniques. (10.1103/PhysRevB.107.165155)
  DOI : 10.1103/PhysRevB.107.165155
• BMS Field Theories with $\mathfrak{u}(1)$ Symmetry
  
  • Bagchi Arjun
  • Chatterjee Ritankar
  • Kaushik Rishabh
  • Pal Sanchari
  • Riegler Max
  • Sarkar.A Debmalya
  Physical Review D, American Physical Society, 2023, 107 (10), pp.106019. We investigate quantum field theories in two dimensions (2d) with an underlying Bondi-van der Burgh-Metzner-Sachs (BMS) symmetry augmented by $\mathfrak{u}(1)$ currents. These field theories are expected to holographically capture features of charged versions of cosmological solutions in asymptotically flat 3d spacetimes called Flat Space Cosmologies (FSCs). We conduct a study of the modular properties of these field theories. The characters for the highest weight representations of the symmetry algebra are constructed, and the partition function of the theory is obtained from them. We derive the density of (primary) states and find the entropy and asymptotic values of the structure constants exploiting the modular properties of the partition function and the torus one-point function. The expression for the asymptotic structure constants shows shifts in the weights and one of the central terms and an extra phase compared to the earlier results in the literature for BMS invariant theories without $\mathfrak{u}(1)$ currents present. We reproduce our field results for the structure constants by a bulk computation involving a scalar probe in the background of a charged FSC. (10.1103/PhysRevD.107.106019)
  DOI : 10.1103/PhysRevD.107.106019
• Holographic duals of evaporating black holes
  
  • Emparan Roberto
  • Luna Raimon
  • Suzuki Ryotaku
  • Tomašević Marija
  • Way Benson
  Journal of High Energy Physics, Springer, 2023, 05, pp.182. We describe the dynamical evaporation of a black hole as the classical evolution in time of a black hole in an Anti-de Sitter braneworld. A bulk black hole whose horizon intersects the brane yields the classical bulk dual of a black hole coupled to quantum conformal fields. The evaporation of this black hole happens when the bulk horizon slides off the brane, making the horizon on the brane shrink. We use a large-D effective theory of the bulk Einstein equations to solve the time evolution of these systems. With this method, we study the dual evaporation of a variety of black holes interacting with colder radiation baths. We also obtain the dual of the collapse of holographic radiation to form a black hole on the brane. Finally, we discuss the evolution of the Page curve of the radiation in our evaporation setups, with entanglement islands appearing and then shrinking during the decreasing part of the curve. (10.1007/JHEP05(2023)182)
  DOI : 10.1007/JHEP05(2023)182
• Femtosecond laser-induced sub-wavelength plasma inside dielectrics. III. Terahertz radiation emission
  
  • Ardaneh Kazem
  • Nishikawa Ken-Ichi
  • Giust Remo
  • Morel Benoit
  • Charpin Pierre-Jean
  • Couairon Arnaud
  • Bonnaud Guy
  • Courvoisier Francois
  Physics of Plasmas, American Institute of Physics, 2023, 30 (1), pp.013301. Electromagnetic radiation within the terahertz (THz) frequency range is of great interest for applications in remote sensing and time-domain spectroscopy. The laser-induced plasmas are promising mediums for generating THz radiation. It has been recently reported that focusing femtosecond Bessel pulses inside dielectrics induces a high aspect ratio over-critical plasmas. Here, we show that the intense resonantly driven electrostatic fields at the so-called critical surface lead to THz radiation emission. Through three-dimensional particle-in-cell simulation and analytical derivation, we have investigated the emission of THz radiation. We show that the THz radiation is associated with a hot population of electrons trapped in ambipolar electric fields of the double layers. (10.1063/5.0126427)
  DOI : 10.1063/5.0126427
• Horizon Strings as 3d Black Hole Microstates
  
  • Bagchi Arjun
  • Grumiller Daniel
  • Sheikh-Jabbari M.M.
  SciPost Physics, SciPost Foundation, 2023, 15 (5), pp.210. We construct microstates of 3d black holes in the Hilbert space of tensionless null strings with non-zero winding along the direction transversal to the horizon. Their combinatorics is compatible with the Bekenstein-Hawking entropy and its semiclassical logarithmic corrections. (10.21468/SciPostPhys.15.5.210)
  DOI : 10.21468/SciPostPhys.15.5.210