275 citations · 1.2k across the 23 of their papers we have counts for
25 papers
On the generalized eigenvalue problem in subspace-based excited state methods for quantum computers
Prince Frederick Kwao, Srivathsan Poyyapakkam Sundar, Brajesh Gupt +1
Solving challenging problems in quantum chemistry is one of the most promising applications of quantum computers. Within the quantum algorithms proposed for problems in excited sta…
Evaluating a quantum-classical quantum Monte Carlo algorithm with Matchgate shadows
Benchen Huang, Yi-Ting Chen, Brajesh Gupt +4
Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry and condensed matter physics. The rapid emergence and de…
Cosmic tango between the very small and the very large: Addressing CMB anomalies through Loop Quantum Cosmology
Abhay Ashtekar, Brajesh Gupt, V. Sreenath
While the standard, six-parameter, spatially flat CDM model has been highly successful, certain anomalies in the cosmic microwave background bring out a tension between this mod…
Towards quantum simulation of spin systems using continuous variable quantum devices
Razieh Annabestani, Brajesh Gupt, Bhaskar Roy Bardhan
We study Bosonic representation of spin Ising model with the application of simulating two level systems using continuous variable quantum processors. We decompose the time evoluti…
Alleviating the Tension in the Cosmic Microwave Background using Planck-Scale Physics
Abhay Ashtekar, Brajesh Gupt, Donghui Jeong +1
Certain anomalies in the CMB bring out a tension between the six-parameter flat CDM model and the CMB data. We revisit the PLANCK analysis with loop quantum cosmology (LQC) pred…
A quantum hardware-induced graph kernel based on Gaussian Boson Sampling
Maria Schuld, Kamil Brádler, Robert Israel +2
A device called a 'Gaussian Boson Sampler' has initially been proposed as a near-term demonstration of classically intractable quantum computation. As recently shown, it can also b…
Classical benchmarking of Gaussian Boson Sampling on the Titan supercomputer
Brajesh Gupt, Juan Miguel Arrazola, Nicolás Quesada +1
Gaussian Boson Sampling is a model of photonic quantum computing where single-mode squeezed states are sent through linear-optical interferometers and measured using single-photon…
Photonic quantum algorithm for Monte Carlo integration
Patrick Rebentrost, Brajesh Gupt, Thomas R. Bromley
We present a continuous-variable photonic quantum algorithm for the Monte Carlo evaluation of multi-dimensional integrals. Our algorithm encodes n-dimensional integration into n+3…
A faster hafnian formula for complex matrices and its benchmarking on a supercomputer
Andreas Björklund, Brajesh Gupt, Nicolás Quesada
We introduce new and simple algorithms for the calculation of the number of perfect matchings of complex weighted, undirected graphs with and without loops. Our compact formulas fo…
Quantum computational finance: Monte Carlo pricing of financial derivatives
Patrick Rebentrost, Brajesh Gupt, Thomas R. Bromley
Financial derivatives are contracts that can have a complex payoff dependent upon underlying benchmark assets. In this work, we present a quantum algorithm for the Monte Carlo pric…
Constraining Planck scale physics with CMB and Reionization Optical Depth
Brajesh Gupt
We present proof of principle for a two way interplay between physics at very early Universe and late time observations. We find a relation between primordial mechanisms responsibl…
Tensor perturbations during inflation in a spatially closed Universe
Béatrice Bonga, Brajesh Gupt, Nelson Yokomizo
In a recent paper [17], we studied the evolution of the background geometry and scalar perturbations in an inflationary, spatially closed Friedmann-Lemaître-Robertson-Walker (FLRW)…
Phenomenology with fluctuating quantum geometries in loop quantum cosmology
Ivan Agullo, Abhay Ashtekar, Brajesh Gupt
The goal of this paper is to probe phenomenological implications of large fluctuations of quantum geometry in the Planck era, using cosmology of the early universe. For the backgro…
Initial conditions for cosmological perturbations
Abhay Ashtekar, Brajesh Gupt
Penrose proposed that the big bang singularity should be constrained by requiring that the Weyl curvature vanishes there. The idea behind this past hypothesis is attractive because…
Quantum Gravity in the Sky: Interplay between fundamental theory and observations
Abhay Ashtekar, Brajesh Gupt
Observational missions have provided us with a reliable model of the evolution of the universe starting from the last scattering surface all the way to future infinity. Furthermore…
Generalized effective description of loop quantum cosmology
Abhay Ashtekar, Brajesh Gupt
The effective description of loop quantum cosmology (LQC) has proved to be a convenient platform to study phenomenological implications of the quantum bounce that resolves the clas…
Phenomenological investigation of a quantum gravity extension of inflation with the Starobinsky potential
Béatrice Bonga, Brajesh Gupt
We investigate the pre-inflationary dynamics of inflation with the Starobinsky potential, favored by recent data from the Planck mission, using techniques developed to study cosmol…
Inflation with the Starobinsky potential in Loop Quantum Cosmology
Béatrice Bonga, Brajesh Gupt
A self-consistent pre-inflationary extension of the inflationary scenario with the Starobinsky potential, favored by Planck data, is studied using techniques from loop quantum cosm…
Numerical evolution of squeezed and non-Gaussian states in loop quantum cosmology
Peter Diener, Brajesh Gupt, Miguel Megevand +1
In recent years, numerical simulations with Gaussian initial states have demonstrated the existence of a quantum bounce in loop quantum cosmology in various models. A key issue per…
Numerical simulations of a loop quantum cosmos: robustness of the quantum bounce and the validity of effective dynamics
Peter Diener, Brajesh Gupt, Parampreet Singh
A key result of isotropic loop quantum cosmology is the existence of a quantum bounce which occurs when the energy density of the matter field approaches a universal maximum close…
Chimera: A hybrid approach to numerical loop quantum cosmology
Peter Diener, Brajesh Gupt, Parampreet Singh
The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In…
Non-singular AdS-dS transitions in a landscape scenario
Brajesh Gupt, Parampreet Singh
Understanding transitions between different vacua of a multiverse allowing eternal inflation is an open problem whose resolution is important to gain insights on the global structu…
A quantum gravitational inflationary scenario in Bianchi-I spacetime
Brajesh Gupt, Parampreet Singh
We investigate the inflationary model in the Bianchi-I spacetime using effective spacetime description of loop quantum cosmology to understand the issues of the resolution of…
Quantum gravitational Kasner transitions in Bianchi-I spacetime
Brajesh Gupt, Parampreet Singh
Due to non-perturbative quantum gravitational effects, the classical big bang singularity is replaced by a quantum big bounce of the mean scale factor in loop quantization of Bianc…