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We suggest a new method to compute the spectrum and wave functions of excited states. We construct a stochastic basis of Bargmann link states, drawn from a physical probability density distribution and compute transition amplitudes between…

High Energy Physics - Lattice · Physics 2010-01-21 H. Kroger , A. Hosseinizadeh , J. F. Laprise , J. Kroger

We review a recent approach for the simulation of many-body interacting systems based on an efficient generalization of the Lanczos method for Quantum Monte Carlo simulations. This technique allows to perform systematic corrections to a…

Strongly Correlated Electrons · Physics 2007-05-23 Sandro Sorella

The power method and block Lanczos method are popular numerical algorithms for computing the truncated singular value decomposition (SVD) and eigenvalue decomposition problems. Especially in the literature of randomized numerical linear…

Numerical Analysis · Computer Science 2015-12-21 Shusen Wang , Zhihua Zhang , Tong Zhang

We present an algorithm to compute Green's functions on quantum computers for interacting electron systems, which is a challenging task on conventional computers. It uses a continued fraction representation based on the Lanczos method,…

Quantum Physics · Physics 2022-12-07 Francois Jamet , Abhishek Agarwal , Ivan Rungger

We investigate the inhomogeneous inflation, in which the space exponentially expands with inhomogeneities, and its cosmological perturbations. The inhomogeneous inflation is realized by introducing scalar fields with spacelike gradients…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-11 Xian Gao , Chao Kang

The decoherence of quantum fluctuations into classical perturbations during inflation is discussed. A simple quantum mechanical argument, using a spatial particle wavefunction rather than a field description, shows that observable…

Astrophysics · Physics 2007-05-23 Craig J. Hogan

We calculate the energy levels of a system of neutrinos undergoing collective oscillations as functions of an effective coupling strength and radial distance from the neutrino source using the quantum Lanczos (QLanczos) algorithm…

Quantum Physics · Physics 2021-04-08 Kübra Yeter-Aydeniz , Shikha Bangar , George Siopsis , Raphael C. Pooser

This paper presents the CMB angular power spectrum obtained using the \texttt{CAMB} code for three different models of inflation: the Starobinsky inflationary model, the generalized Starobinsky inflationary model, and the chaotic…

General Relativity and Quantum Cosmology · Physics 2024-10-23 Daniel Pozo , Lenin Calvache , Esteban Orozco , Vicente A. Arévalo , Clara Rojas

We study the primordial tensor perturbation produced from the double inflationary scenario with an intermediate break stage. Because of the transitions, the power spectrum deviates from the vacuum one and there will appear oscillatory…

General Relativity and Quantum Cosmology · Physics 2019-07-08 Shi Pi , Misao Sasaki , Ying-li Zhang

We show how the choice of an inflationary state that entangles scalar and tensor fluctuations affects the angular two-point correlation functions of the $T$, $E$, and $B$ modes of the cosmic microwave background. The propagators for a state…

High Energy Physics - Theory · Physics 2016-12-14 Hael Collins , Tereza Vardanyan

We calculate the bispectrum of primordial curvature perturbations, \zeta, generated during "open inflation." Inflation occurs inside a bubble nucleated via quantum tunneling from the background false vacuum state. Our universe lives inside…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Kazuyuki Sugimura , Eiichiro Komatsu

In the context of two-field inflation characterized by a light direction and a heavy direction, we revisit the question of the impact of the massive modes on the power spectrum produced after a turn in the inflationary trajectory. We…

High Energy Physics - Theory · Physics 2014-03-04 Xian Gao , David Langlois , Shuntaro Mizuno

The Altshuler-Shklovskii formulas [1] predict, for any disordered quantum system in the diffusive regime, a universal power law behaviour for the correlation functions of the mesoscopic eigenvalue density. In this paper and its companion…

Probability · Mathematics 2014-03-21 Laszlo Erdos , Antti Knowles

We analyse the dynamics of spinodal decomposition in inflationary cosmology using the closed time path formalism of out of equilibrium quantum field theory combined with the non-perturbative Hartree approximation. In addition to a general…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Cormier , R. Holman

We study the effects of the Gauss-Bonnet term on the energy spectrum of inflationary gravitational waves. The models of inflation are classified into two types based on their predictions for the tensor power spectrum: red-tilted ($n_T<0$)…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-15 Seoktae Koh , Bum-Hoon Lee , Gansukh Tumurtushaa

We study Krylov complexity of a one-dimensional Bosonic system, the celebrated Bose-Hubbard Model. The Bose-Hubbard Hamiltonian consists of interacting bosons on a lattice, describing ultra-cold atoms. Apart from showing superfluid-Mott…

High Energy Physics - Theory · Physics 2024-01-02 Arpan Bhattacharyya , Debodirna Ghosh , Poulami Nandi

We develop a systematic framework to compute the primordial power spectrum up to next-to-next-to-next to leading order (N3LO) in the Hubble-flow parameters for a large class of effective theories of inflation. We assume that the quadratic…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Eugenio Bianchi , Mauricio Gamonal

Recent combined results from the Wilkinson Microwave Anisotropy Probe (WMAP) and Sloan Digital Sky Survey (SDSS) provide a remarkable set of data which requires more accurate and general investigation. Here we derive formulae for the power…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jeongyeol Choe , Jinn-Ouk Gong , Ewan D. Stewart

We use holographic techniques to compute inflationary non-Gaussianities for general single-field inflation, including models with a non-trivial sound speed. In this holographic approach, the inflationary dynamics is captured by a relevant…

High Energy Physics - Theory · Physics 2016-12-14 Hiroshi Isono , Toshifumi Noumi , Gary Shiu , Sam S. C. Wong , Siyi Zhou

We invert the second order, single field, general slow-roll formula for the power spectrum, to obtain a second order formula for inflationary parameters in terms of the primordial power spectrum.

Astrophysics · Physics 2009-11-13 Minu Joy , Ewan D. Stewart