A5014820609- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Computational Physics and Python Applications
- Relativity and Gravitational Theory
- Atomic and Subatomic Physics Research
- Stochastic processes and financial applications
- Noncommutative and Quantum Gravity Theories
- Astronomy and Astrophysical Research
- advanced mathematical theories
- Neutrino Physics Research
- Geophysics and Sensor Technology
- Gyrotron and Vacuum Electronics Research
- Adaptive optics and wavefront sensing
- Advanced Mathematical Theories and Applications
- Hydrological Forecasting Using AI
- Experimental and Theoretical Physics Studies
- Astrophysics and Cosmic Phenomena
- Complex Systems and Time Series Analysis
Tsinghua University
2011-2024
Collaborative Innovation Center of Quantum Matter
2022
Harvard University
2016-2021
Mathematical Sciences Research Institute
2016-2019
Harvard University Press
2018
Institute of Modern Physics
2013-2014
King's College London
2014
A bstract The most general tree-level boundary correlation functions of quantum fields in inflationary spacetime involve multiple exchanges massive states the bulk, which are technically difficult to compute due multi-layer nested time integrals Schwinger-Keldysh formalism. On other hand, correlators with well motivated cosmological collider physics, original quasi-single-field inflation model as a notable example. In this work, partial Mellin-Barnes representation, we derive simple rule,...
We present a systematic introduction to the diagrammatic method for practical calculations in inflationary cosmology, based on Schwinger-Keldysh path integral formalism. show particular that rules can be derived directly from classical Lagrangian even presence of derivative couplings. Furthermore, we use quasi-single-field inflation model as an example how this formalism, combined with trick mixed propagator, significantly simplify calculation some in-in correlation functions. The resulting...
We look for oscillating signals in the primordial bispectrum from new physics heavy particles which are visibly large next generation scale structures (LSS) survey. show that ordinary inflation scenarios where a slow-rolling inflaton generates density fluctuations and with no breaking of invariance or spacetime symmetry, there exist naturally unless rolling parity-odd chemical potential particles. estimate accessibility this signal through observations. While current CMB data already...
In direct analogy to the 4-body decay of a heavy scalar particle, 4-point correlation function primordial fluctuations carries P and CP information. The violation appears as P-odd angular dependence in imaginary part trispectrum momentum space. We construct model with axion-like couplings which leads observably large CP-violating for future surveys. Furthermore, we show importance on-shell particle production observing P- signals. It is impossible observe these signals from local 4-scalar...
We initiate a systematic study of precision calculation the inflation correlators at 1-loop level, starting in this paper with bosonic bispectrum chemical-potential enhancement. Such processes could lead to important cosmological collider observables but are notoriously difficult compute due lack symmetries. attack problem from direct numerical approach based on real-time Schwinger-Keldysh formalism and show full results for arbitrary kinematics containing both oscillatory "signals"...
A bstract We study the theory and phenomenology of massive spin-2 fields during inflation with nonzero background chemical potential, extend cosmological collider physics to tensor modes. identify a unique dimension-5 parity-violating potential operator for fields, which leads ghost-free linear propagating one scalar mode two The greatly boosts production even very heavy particles, thereby large distinct signals particles. show up at tree-level in both curvature trispectrum tensor-curvature...
A bstract Massive particles produced during the cosmic inflation can imprint in primordial non-Gaussianities as characteristic oscillating functions of various momentum ratios, known cosmological collider signals. We initiate a study phase signals which be unambiguously defined and measured. The provide useful new information about spin couplings intermediate heavy that cannot obtained from signal frequency angular dependences alone. also present analytical results for full nonlocal two...
Massive spinning particles acquire helicity-dependent chemical potentials during the inflation from axion-type couplings. Such fields can mediate sizable inflaton correlators which we call helical correlators. Helical are approximately scale invariant, dS boost breaking, parity-violating, and promising observables of cosmological collider physics. In this work, present complete analytical results for 4-point with tree-level exchanges massive particles, including both smooth background...
Leptogenesis is generally challenging to directly test due the very high energy scales involved. In this Letter, we propose a new probe for leptogenesis with cosmological collider physics. With example of Higgs collider, demonstrate that during inflation models can produce detectable primordial non-Gaussianity distinctive oscillatory patterns encode information about lepton-number violating couplings, Majorana right-hand neutrino masses, and CP phases, which are essential leptogenesis.
Large-field inflation is a major class of models featuring near- or super-Planckian excursion the inflaton field. We point out that large generically introduces significant scale dependence to spectator fields through couplings, which in turn induces characteristic distortions oscillatory shape primordial bispectrum mediated by This so-called cosmological collider signal can thus be useful indicator field excursions. show an explicit example with signals from "tower states" motivated...
Phenomenological studies of cosmological collider physics in recent years have identified many 1-loop inflation correlators as leading channels for discovering heavy new particles around or above the scale. However, complete analytical results these massive are currently unavailable. In this work, we embark on a program bootstrapping with exchanges at order, input tree-level and techniques spectral decomposition dS. As first step, present time class 4-point 3-point mediated by scalar fields...
We derive exact and closed-form expressions for a large class of two-point three-point inflation correlators with the tree-level exchange single massive particle. The intermediate particle is allowed to have arbitrary mass, spin, chemical potential, nonderivative or derivative couplings external inflaton modes. also allow coupling coefficients complex power dependences on conformal time. Our results feature involving only familiar special functions without any infinite sums. This achieved by...
A bstract Inflation correlators with one-loop massive exchange encode rich information about the dynamics of loop particles. Their nonanalytic behavior in certain soft limits leads to characteristic oscillatory pattern, which is leading signal many particle models cosmological collider physics. In this work, we investigate systematically such nonanalyticity for arbitrary one-particle-irreducible (1PI) various limits. With partial Mellin-Barnes representation, present and prove a...
A bstract The dynamics of quantum fields during cosmic inflation can be probed via their late-time boundary correlators. analytic structure these correlators contains rich physical information bulk dynamics, and is also closely related to cosmological collider observables. In this work, we study a particular type nonanalytic behavior, called nonlocal signals, for with massive exchanges at arbitrary loop orders. We propose signal-detection algorithm identify all possible sources signals in an...
We study gravitational interaction of Higgs boson through the unique dimension-4 operator ξH†H, with H doublet and Ricci scalar curvature. analyze effect this dimensionless nonminimal coupling ξ on weak gauge scattering in both Jordan Einstein frames. explicitly establish longitudinal-Goldstone equivalence theorem nonzero frames, unitarity constraints. ξ-induced cross sections at (1−30) TeV scales, propose to probe Higgs-gravity via experiments LHC (14 TeV) next generation pp colliders...
The China Dark Matter Experiment Collaboration reports the first experimental limit on weakly interacting massive particles (WIMPs) dark matter from 14.6 kg-days of data taken with a 994 g p-type point-contact germanium detector at Jinping underground laboratory where rock overburden is more than 2400 m. energy threshold achieved was 400 eVee. According to kg-day live data, we placed...
A bstract We study the cosmological collider phenomenology of neutrinos in an effective field theory. The mass spectrum and their characteristic oscillatory signatures squeezed limit bispectrum are computed. Both dS-covariant slow-roll corrections considered, so is scenario electroweak symmetry breaking during inflation. Interestingly, we show that background inflaton provides a chemical potential for neutrino production. greatly amplifies signal makes observably large heavy without need fine tuning.
A bstract The quantum fluctuations of the Higgs field during inflation could be a source primordial density perturbations through Higgs-dependent inflaton decay. By measuring non-Gaussianities, this so-called Higgs-modulated reheating scenario provides us unique chance to probe interactions at extremely high energy scale, which we call Cosmological Collider (CHC). We realize CHC in simple where decays into Higgs-portal scalars, taking account decay fluctuation amplitude after inflation. also...
A bstract We study the production of massive gauge bosons during inflation from axion-type coupling to inflaton and corresponding oscillatory features in primordial non-Gaussianity. In a window which both boson mass chemical potential are large, signal is potentially reachable by near-future large scale structure probes. This scenario covers new region oscillation frequency not populated previously known cosmological collider models. also demonstrate how properly include exponential factor...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
A bstract The correlators of large-scale fluctuations belong to the most important observables in modern cosmology. Recently, there have been considerable efforts analytically understanding cosmological and related wavefunction coefficients, which we collectively call amplitudes. In this work, provide a set simple rules directly write down analytical answers for arbitrary tree-level amplitudes conformal scalars with time-dependent interactions power-law FRW universe. With recently proposed...
We work out the Standard Model (SM) mass spectrum during inflation with quantum corrections, and explore its observable consequences in squeezed limit of non-Gaussianity. Both non-Higgs Higgs models are studied detail. also illustrate how some inflationary loop diagrams can be computed neatly by Wick-rotating background to Euclidean signature dimensional regularization.
Light scalar fields typically develop spatially varying backgrounds during inflation. Very often they do not directly affect the density perturbations, but interact with other that leave nontrivial signals in primordial perturbations. In this sense become "missing scalars" at cosmological collider. We study potentially observable of these missing scalars, focusing on a special example where distorts usual oscillatory features squeezed bispectrum. The distortion is also useful signal...
A bstract Inflation correlators with massive exchanges are central observables of cosmological collider physics, and also important theoretical data for us to better understand quantum field theories in dS. However, they difficult compute directly due many technical complications the Schwinger-Keldysh integral. In this work, we initiate a new bootstrap program inflation dispersion relations on complex momentum planes. We classify kinematic variables correlator into vertex energies line...
With the LHC discovery of a 125 GeV Higgs-like boson, we study gravitational interaction Higgs boson via unique dimension-4 operator involving doublet and scalar curvature, $\,\xi H^\dag H R\,$, with nonminimal coupling $\,\xi\,$. This portal term can be transformed away in Einstein frame induces gauge-invariant effective interactions sector. We weak scattering frame, explicitly demonstrate longitudinal-Goldstone equivalence theorem presence $\,\xi\,$ coupling. these, derive unitarity bound...