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Related papers: Inflationary complexity of thermal state

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Many quantum gravitational frameworks, such as DBI inflation, k-essence, and effective field theories obtained by integrating out heavy modes, can lead to a non-trivial sound speed. Meanwhile, our universe can be described as an open…

General Relativity and Quantum Cosmology · Physics 2026-02-27 Shi-Cheng Liu , Lei-Hua Liu , Bichu Li , Hai-Qing Zhang , Peng-Zhang He

In this work, we have systematically investigated the Krylov complexity of curvature perturbation for the modified dispersion relation in inflation, using the algorithm in closed system and open system. Our analysis could be applied to the…

High Energy Physics - Theory · Physics 2024-05-24 Tao Li , Lei-Hua Liu

Thermal interactions are ubiquitous in the cosmos, driving systems toward equilibrium. In this work, we investigate the evolution of thermal states across the early universe, encompassing the inflationary, radiation-dominated (RD), and…

High Energy Physics - Theory · Physics 2026-03-17 Tao Li , Lei-Hua Liu

In this paper, we study the impact of non-trivial sound on the evolution of cosmological complexity in inflationary period. The vacuum state of curvature perturbation could be treated as squeezed states with two modes, characterized by the…

General Relativity and Quantum Cosmology · Physics 2022-10-19 Lei-Hua Liu , Ai-Chen Li

The Lanczos algorithm offers a framework for constructing wave functions in closed and open quantum systems from their Hamiltonians. Since the early universe is inherently an open system, we employ this algorithm to investigate Krylov…

High Energy Physics - Theory · Physics 2026-03-17 Ke-Hong Zhai , Lei-Hua Liu

In this paper, we study the Krylov complexity ($K$) from the planar/inflationary patch of the de Sitter space using the two mode squeezed state formalism in the presence of an effective field having sound speed $c_s$. From our analysis, we…

High Energy Physics - Theory · Physics 2023-06-09 Kiran Adhikari , Sayantan Choudhury

Krylov complexity characterizes the operator growth in the quantum many-body systems or quantum field theories. The existing literatures have studied the Krylov complexity in the low temperature limit in the quantum field theories. In this…

High Energy Physics - Theory · Physics 2024-11-15 Peng-Zhang He , Hai-Qing Zhang

Complexity will be more and more essential in high-energy physics. It is naturally extended into the very early universe. Considering the universe as a quantum chaotic system, the curvature perturbation of the scalar field is identified…

General Relativity and Quantum Cosmology · Physics 2024-05-24 Tao Li , Lei-Hua Liu

The inflationary cosmology is analyzed from the point of view of squeezed quantum states. As noted by Grishchuk and Sidorov, the amplification of quantum fluctuations into macroscopic perturbations which occurs during cosmic inflation is a…

Astrophysics · Physics 2010-04-08 Andreas Albrecht , Pedro Ferreira , Michael Joyce , Tomislav Prokopec

The initial quantum state during inflation may evolve to a highly squeezed quantum state due to the amplification of the time-dependent parameter, $\omega_{phys}(k/a)$, which may be the modified dispersion relation in trans-Planckian…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Seoktae Koh , Sang Pyo Kim , Doo Jong Song

We continue the analysis of the Krylov complexity in the IP matrix model. In a previous paper, for a fundamental operator, it was shown that at zero temperature, the Krylov complexity oscillates and does not grow, but in the infinite…

High Energy Physics - Theory · Physics 2023-08-17 Norihiro Iizuka , Mitsuhiro Nishida

The spectrum of inflationary tensor perturbations is one of the very few available probes of the post-inflationary reheating epoch, and it is strongly influenced by the Universe's equation of state during this period. In the current era of…

General Relativity and Quantum Cosmology · Physics 2025-06-11 Avirup Ghosh , Deep Ghosh

Considering the large-$q$ expansion of the Sachdev-Ye-Kitaev (SYK) model in the two-stage limit, we compute the Lanczos coefficients, Krylov complexity, and the higher Krylov cumulants in subleading order, along with the $t/q$ effects. The…

High Energy Physics - Theory · Physics 2023-08-21 Budhaditya Bhattacharjee , Pratik Nandy , Tanay Pathak

We investigate the complexity of states and operators evolved with the modular Hamiltonian by using the Krylov basis. In the first part, we formulate the problem for states and analyse different examples, including quantum mechanics,…

High Energy Physics - Theory · Physics 2023-06-27 Pawel Caputa , Javier M. Magan , Dimitrios Patramanis , Erik Tonni

We study thermalization in closed non-integrable quantum systems using the Krylov basis. We demonstrate that for thermalization to occur, the matrix representation of typical local operators in the Krylov basis should exhibit a specific…

Quantum Physics · Physics 2025-01-23 Mohsen Alishahiha , Mohammad Javad Vasli

Krylov complexity is a novel measure of operator complexity that exhibits universal behavior and bounds a large class of other measures. In this letter, we generalize Krylov complexity from a closed system to an open system coupled to a…

Strongly Correlated Electrons · Physics 2023-08-11 Chang Liu , Haifeng Tang , Hui Zhai

We investigate the phenomenology of warm inflation and present generic results about the evolution of the inflaton and radiation fields. The general conditions required for warm inflation to take place are derived and discussed. A…

Astrophysics · Physics 2009-10-31 A. N. Taylor , A. Berera

Warm inflation is commonly studied under the assumption that the stochastic force sourcing inflaton fluctuations is Markovian. Realistic thermal systems, however, possess finite relaxation times and can therefore generate colored noise with…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-13 Mayukh R. Gangopadhyay , Nilanjana Kumar

In this work, we systematically investigate the quantum-information diagnostics of cosmological perturbations with a nontrivial sound speed, utilizing a normalized open two-mode squeezed-state framework. Rather than introducing new…

General Relativity and Quantum Cosmology · Physics 2026-04-24 Shi-Cheng Liu , Lei-Hua Liu , Bichu Li , Hai-Qing Zhang , Peng-Zhang He

Recently, the concept of spread complexity, Krylov complexity for states, has been introduced as a measure of the complexity and chaoticity of quantum systems. In this paper, we study the spread complexity of the thermofield double state…

High Energy Physics - Theory · Physics 2024-05-27 Kyoung-Bum Huh , Hyun-Sik Jeong , Juan F. Pedraza
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