Brajesh Gupt

ORCID: 0000-0002-6352-8342
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About
Contact & Profiles
Research Areas
  • Black Holes and Theoretical Physics
  • Cosmology and Gravitation Theories
  • Noncommutative and Quantum Gravity Theories
  • Quantum Computing Algorithms and Architecture
  • Quantum Information and Cryptography
  • Galaxies: Formation, Evolution, Phenomena
  • Quantum Electrodynamics and Casimir Effect
  • Advanced Graph Theory Research
  • Neural Networks and Reservoir Computing
  • Relativity and Gravitational Theory
  • Graph theory and applications
  • Matrix Theory and Algorithms
  • Optical Network Technologies
  • Algebraic and Geometric Analysis
  • Quantum and electron transport phenomena
  • Quantum Mechanics and Applications
  • Geometric Analysis and Curvature Flows
  • Meteorological Phenomena and Simulations
  • Advanced Mathematical Theories and Applications
  • Quantum Mechanics and Non-Hermitian Physics
  • Neuroblastoma Research and Treatments
  • Solar and Space Plasma Dynamics
  • Semiconductor materials and devices
  • Machine Learning in Materials Science
  • Computational Physics and Python Applications

Pennsylvania State University
2015-2021

The University of Texas at Austin
2020-2021

Xanadu Quantum Technologies (Canada)
2018-2020

Louisiana State University
2012-2017

Louisiana State University Agricultural Center
2014

Financial derivatives are contracts that can have a complex payoff dependent upon underlying benchmark assets. In this work, we present quantum algorithm for the Monte Carlo pricing of financial derivatives. We show how relevant probability distributions be prepared in superposition, functions implemented via circuits, and price extracted measurements. amplitude estimation applied to achieve quadratic speedup number steps required obtain an estimate with high confidence. This work provides...

10.1103/physreva.98.022321 article EN Physical review. A/Physical review, A 2018-08-20

A key result of isotropic loop quantum cosmology is the existence a bounce which occurs when energy density matter field approaches universal maximum close to Planck density. Though has been exhibited in various models, due severe computational challenges, some important questions have so far remained unaddressed. These include demonstration for widely spread states, its detailed properties states probes regions volume and reliability continuum effective spacetime description general. In...

10.1088/0264-9381/31/10/105015 article EN Classical and Quantum Gravity 2014-05-06

A device called a 'Gaussian Boson Sampler' has initially been proposed as near-term demonstration of classically intractable quantum computation. As recently shown, it can also be used to decide whether two graphs are isomorphic. Based on these results we construct feature map and graph similarity measure or 'graph kernel' using samples from the device. We show that kernel performs well compared standard kernels typical benchmark datasets, provide theoretical motivation for this success,...

10.1103/physreva.101.032314 article EN publisher-specific-oa Physical review. A/Physical review, A 2020-03-11

Observational missions have provided us with a reliable model of the evolution universe starting from last scattering surface all way to future infinity.Furthermore given specific inflation, using quantum field theory on curved space-times this history can be pushed back in time epoch when space-time curvature was some 10 62 times that at horizon solar mass black hole!However, extend further Planck regime requires input gravity.An important aspect is choice background geometry and Heisenberg...

10.1088/1361-6382/34/1/014002 article EN Classical and Quantum Gravity 2016-12-08

In recent years, numerical simulations with Gaussian initial states have demonstrated the existence of a quantum bounce in loop cosmology various models.A key issue pertaining to robustness and associated physics is understand evolution for more general which may depart significantly from Gaussianity no well defined peakedness properties.The analysis such states, including squeezed highly non-Gaussian has been computationally challenging until now.In this manuscript, we overcome these...

10.1088/0264-9381/31/16/165006 article EN Classical and Quantum Gravity 2014-08-01

We introduce new and simple algorithms for the calculation of number perfect matchings complex weighted, undirected graphs with without loops. Our compact formulas hafnian loop n × matrices run in O ( 3 2 /2 ) time, are embarrassingly parallelizable and, to best our knowledge, fastest exact compute these quantities. Despite highly optimized algorithm, numerical benchmarks on Titan supercomputer up size 56 indicate that one would require 288,000 CPUs this machine about 6 weeks a 100 matrix.

10.1145/3325111 article EN ACM Journal of Experimental Algorithmics 2019-06-11

Gupt et al., (2019). The Walrus: a library for the calculation of hafnians, Hermite polynomials and Gaussian boson sampling. Journal Open Source Software, 4(44), 1705, https://doi.org/10.21105/joss.01705

10.21105/joss.01705 article EN cc-by The Journal of Open Source Software 2019-12-19

Certain anomalies in the CMB bring out a tension between six-parameter flat $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model and data. We revisit PLANCK analysis with loop quantum cosmology (LQC) predictions show that LQC alleviates both large-scale power anomaly lensing amplitude. These differences arise because, LQC, primordial spectrum is scale dependent for small $k$, specific suppression. conclude prediction of larger optical depth suppression $B$-mode polarization on large scales.

10.1103/physrevlett.125.051302 article EN Physical Review Letters 2020-07-29

A characteristic feature of loop quantization the isotropic and Bianchi-I spacetimes is existence universal bounds on energy density expansion shear scalars, independent matter content. We investigate properties these physical quantities in Bianchi-II Bianchi-IX spacetimes, which have been recently quantized using connection operator approach. Using effective Hamiltonian approach, we show that for spacetime, scalars turn out to be bounded, albeit not by values. In when approach classical...

10.1103/physrevd.85.044011 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2012-02-07

Due to non-perturbative quantum gravitational effects, the classical big bang singularity is replaced by a bounce of mean scale factor in loop quantization Bianchi-I spacetime. An important issue understand various differences physical properties spacetime across bounce. We investigate this context geometrical structures, identified Kasner exponents metric, which arise on approach theory. Using effective description model cosmology with dust, radiation and stiff matter, we find that as...

10.1103/physrevd.86.024034 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2012-07-23

We investigate the pre-inflationary dynamics of inflation with Starobinsky potential, favored by recent data from Planck mission, using techniques developed to study cosmological perturbations on quantum spacetimes in framework loop cosmology. find that for a large part initial data, compatible observations occurs. There exists subset this leads gravity signatures are potentially observable. Interestingly, despite different inflationary dynamics, these corrections powerspectra similar those...

10.1103/physrevd.93.063513 article EN publisher-specific-oa Physical review. D/Physical review. D. 2016-03-14

Penrose proposed that the big bang singularity should be constrained by requiring Weyl curvature vanishes there. The idea behind this past hypothesis is attractive because it constrains initial conditions for universe in geometric terms and not confined to a specific early paradigm. However, precise statement of Penrose's tied classical space-times furthermore restricts only gravitational degrees freedom. These are encapsulated tensor modes commonly used cosmological perturbation theory....

10.1088/1361-6382/aa52d4 article EN Classical and Quantum Gravity 2016-12-29

The effective description of loop quantum cosmology (LQC) has proved to be a convenient platform study phenomenological implications the bounce that resolves classical big bang singularity. Originally, this was derived using Gaussian states with small dispersions. In paper we present generalization incorporate large Specifically, derive generalized Friedmann and Raychaudhuri equations propose Hamiltonian which are being used in an ongoing consequences broad class geometries. We also discuss...

10.1103/physrevd.92.084060 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2015-10-28

10.1007/s10714-016-2071-0 article EN General Relativity and Gravitation 2016-05-11

While the standard, six-parameter, spatially flat $\Lambda$CDM model has been highly successful, certain anomalies in cosmic microwave background bring out a tension between this and observations. The statistical significance of any one anomaly is small. However, taken together, presence two or more them imply that according to standard inflationary theories we live quite an exceptional universe. We revisit analysis PLANCK collaboration using loop quantum cosmology, where unforeseen...

10.3389/fspas.2021.685288 article EN cc-by Frontiers in Astronomy and Space Sciences 2021-06-04

Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry condensed matter physics. The rapid emergence development computers offer promising route systematically tackle this problem. Recent work by [Huggins , ] proposed hybrid quantum-classical Monte Carlo (QC-QMC) algorithm using Clifford shadows determine ground state Fermionic Hamiltonian. This approach displayed inherent noise resilience potential for improved compared...

10.1103/physrevresearch.6.043063 article EN cc-by Physical Review Research 2024-10-24

We investigate the ϕ2 inflationary model in Bianchi-I spacetime using effective description of loop quantum cosmology to understand issues resolution initial singularity, isotropization, effect anisotropies on amount inflation, and phase-space attractors presence non-perturbative gravitational modifications. A comparative analysis with classical theory by including more general conditions than ones previously considered latter is also performed. show that, general, singularity replaced a...

10.1088/0264-9381/30/14/145013 article EN Classical and Quantum Gravity 2013-06-20

The goal of this paper is to probe phenomenological implications large fluctuations quantum geometry in the Planck era, using cosmology early universe. For background (Friedmann, Lemaître, Robertson, Walker) \emph{quantum} geometry, we allow `widely spread' states which \emph{relative} dispersions are as $168\%$ regime. By introducing suitable methods overcome ensuing conceptual and computational issues, calculate power spectrum $P_{\mathcal{R}}(k)$ spectral index $n_s(k)$ primordial...

10.1088/1361-6382/aa60ec article EN Classical and Quantum Gravity 2017-02-16

The existence of a quantum bounce in isotropic spacetimes is key result loop cosmology (LQC), which has been demonstrated to arise all the models studied so far. In most models, using numerical simulations involving states are sharply peaked and at volumes much larger than Planck volume. An important issue confirm for have wide spread, or closer Numerical with such demand large computational domains, making them very expensive practically infeasible techniques implemented To overcome these...

10.1088/0264-9381/31/2/025013 article EN Classical and Quantum Gravity 2013-12-05

Understanding transitions between different vacua of a multiverse allowing eternal inflation is an open problem whose resolution important to gain insights on the global structure spacetime as well measure. In classical theory, from anti--de Sitter de are forbidden due big-crunch singularity. this paper, we consider toy landscape potentials: double and triple potential vacua, in effective dynamics loop quantum cosmology for $k=\ensuremath{-}1$ FRW model. We show that nonperturbative gravity...

10.1103/physrevd.89.063520 article EN Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2014-03-17

Recent cosmic microwave background (CMB) observations put strong constraints on the spatial curvature via estimation of parameter $\Omega_k$ assuming an almost scale invariant primordial power spectrum. We study evolution geometry and gauge-invariant scalar perturbations in inflationary closed FLRW model calculate find that dynamics is modified due to presence curvature, leading corrections nearly spectrum at end inflation. When evolved surface last scattering, resulting temperature...

10.1088/1475-7516/2016/10/031 article EN Journal of Cosmology and Astroparticle Physics 2016-10-19

Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry condensed matter physics. The rapid emergence development computers offer promising route systematically tackle this problem. Recent work by Huggins et al.[1] proposed hybrid quantum-classical Monte Carlo (QC-QMC) algorithm using Clifford shadows determine ground state Fermionic Hamiltonian. This approach displayed inherent noise resilience potential for improved...

10.48550/arxiv.2404.18303 preprint EN arXiv (Cornell University) 2024-04-28

In a recent paper [1], we studied the evolution of background geometry and scalar perturbations in an inflationary, spatially closed Friedmann-Lemaȋtre-Robertson-Walker (FLRW) model having constant positive spatial curvature topology S3. Due to curvature, early phase slow-roll inflation is modified, leading suppression power spectrum at large angular scales. this paper, extend analysis include tensor perturbations. We find that, similarly perturbations, also shows for long wavelength modes....

10.1088/1475-7516/2017/05/021 article EN Journal of Cosmology and Astroparticle Physics 2017-05-10
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