A5065591060- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Black Holes and Theoretical Physics
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- Experimental Learning in Engineering
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Teaching and Learning Programming
- Computational Physics and Python Applications
- Innovative Teaching Methods
- Gamma-ray bursts and supernovae
- Experimental and Theoretical Physics Studies
- Nonlinear Waves and Solitons
- Noncommutative and Quantum Gravity Theories
- Astrophysics and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Geometry and complex manifolds
- Groundwater flow and contamination studies
- Scientific Research and Discoveries
- Non-Destructive Testing Techniques
Wentworth Institute of Technology
2024
Skidmore College
2021-2023
Tufts University
2014-2023
University of the Basque Country
2018-2021
Ikerbasque
2019-2021
Cosmic string networks offer one of the best prospects for detection cosmological gravitational waves (GWs). The combined incoherent GW emission a large number loops leads to stochastic background (SGWB), which encodes properties network. In this paper we analyze ability Laser Interferometer Space Antenna (LISA) measure background, considering leading models networks. We find that LISA will be able probe cosmic strings with tensions Gμ ≳ (10−17), improving by about 6 orders magnitude current...
We compare the spectrum of stochastic gravitational wave background produced in several models cosmic strings with common-spectrum process recently reported by NANOGrav. discuss theoretical uncertainties computing such a background, and show that despite uncertainties, remain good explanation for potential signal, but consequences string parameters depend on model. Superstrings could also explain only restricted parameter space where their network behavior is effectively identical to...
LISA, the Laser Interferometer Space Antenna, will usher in a new era gravitational-wave astronomy. As first anticipated space-based detector, it expand our view to millihertz sky, where spectacular variety of interesting sources abound: from millions ultra-compact binaries Galaxy, mergers massive black holes at cosmological distances; beginnings inspirals that venture into ground-based detectors' death spiral compact objects holes, and many between. Central realising LISA's discovery...
We initiate the LISA template databank for stochastic gravitational wave backgrounds sourced by cosmic strings. include two templates, an analytical template, which enables more flexible searches, and a numerical derived directly from large Nambu-Goto simulations of string networks. Using searches based on these we forecast parameter space within reach experiment precision with their parameters will be reconstructed, provided signal is observed. The reconstruction permits probing Hubble...
Abstract While supermassive black hole (SMBH) binaries are not the only viable source for low-frequency gravitational wave background (GWB) signal evidenced by most recent pulsar timing array (PTA) data sets, they expected to be likely. Thus, connecting measured PTA GWB spectrum and underlying physics governing demographics dynamics of SMBH is extremely important. Previously, Gaussian processes (GPs) dense neural networks have been used make such a connection being built as conditional...
Abstract We initiate the LISA template databank for stochastic gravitational wave backgrounds sourced by cosmic strings. include two templates, an analytical template, which enables more flexible searches, and a numerical derived directly from large Nambu-Goto simulations of string networks. Using searches based on these we forecast parameter space within reach experiment precision with their parameters will be reconstructed, provided signal is observed. The reconstruction permits probing...
We present the results of computational gravitational backreaction on simple models cosmic string loops. These give us insight into general behavior cusps and kinks loops, in addition to other features evolution. Kinks are rounded off via an asymmetric divergent correction direction. The result is that emerge place kinks, but resulting smooth section has a small amount energy. Existing persist, quickly lose strength as removes energy from surrounding cusp. Both have their location space...
A network of cosmic strings would lead to gravitational waves which may be detected by pulsar timing or future interferometers. The details the wave signal depend on distribution string loops, are produced intercommutations from scaling long strings. We analyze limits imposed energy conservation, i.e., fact that total amount flowing into loops cannot exceed leaving show some recent suggestions for loop production rate and ruled out these limits. As a result, based such suggestions, in...
We calculate the metric and affine connection due to a piecewise linear cosmic string loop, effect of gravitational backreaction for Garfinkle-Vachaspati loop with four straight segments. As expected, reduces size in accord energy going into waves. The ``square'' (maximally symmetric) evaporates without changing shape, but all other loops this class, kinks become less sharp segments between curved. If is close square case, it will evaporate before its are significantly changed; if far from...
We analyze the effect of gravitational backreaction on cosmic string loops with kinks, which is an important determinant shape, and thus potential observability, may exist in Universe today. Kinks are not rounded off, but be straightened out. This means that will only cause kinks to develop cusps after some potentially large fraction their lifetimes. In loops, symmetries prevent even this process, so loop evaporates a self-similar fashion unchanged. As example, we discuss rectangular...
Quantum mechanics makes the otherwise stable vacua of a theory metastable through nucleation bubbles new vacuum. This in turn causes first order phase transition. These cosmological transitions may have played an important role settling our universe into its current vacuum, and they also happen future. The most frameworks where vacuum decay happens contain large number fields. Unfortunately, calculating tunneling rates these models is very time-consuming. In this paper we present simple...
We find the leading-order effect of gravitational back-reaction on cosmic strings for points near kinks and cusps. Near a kink, diverges as inverse cube root distance to acts in direction transverse worldsheet. Over time kink is rounded off, but only regions fairly close are significantly affected. cusps, linearly with cusp, against cusp motion. This results fractional loss string energy that logarithmically closest approach cusp.
We show that one can find de Sitter critical points (saddle points) in models of flux compactification Type IIB String Theory without any uplifting terms and the presence several moduli. demonstrate this by giving explicit examples following some ideas recently presented Conlon [1], as well more generic situations where violate strong form Swampland Conjecture. stabilize complex structure dilaton with fluxes, we introduce a racetrack potential fixes K\"ahler The resultant potentials...
We report on a new class of flux vacua generically present in Calabi-Yau compactifications type-IIB string theory. At these vacua, the mass spectrum complete axiodilaton/complex structure sector is given, to leading order ${\ensuremath{\alpha}}^{\ensuremath{'}}$ and ${g}_{s}$, by simple analytic formula independent choice Calabi-Yau. provide method find construct an ensemble 17,054 solutions for hypersurface ${\mathbb{WP}}_{[1,1,1,6,9]}^{4}$, where masses axiodilaton 272 complex fields can...
We quantitatively analyze a familiar classroom demonstration, Van Waltenhofen's eddy current pendulum, to predict the damping effect for variety of plate geometries from first principles. Results conformal mapping, finite element simulations and simplified model suitable introductory classes are compared with experiments.
Charge carriers moving at the speed of light along a straight, superconducting cosmic string carry with them logarithmically divergent slab electromagnetic field energy. Thus no finite local input can induce current that travels unimpeded to infinity. Rather, back-reaction must damp this asymptotically nothing. We compute and find fields currents decline exactly as rapidly necessary prevent divergence. briefly discuss corresponding gravitational situation.
I describe the assessment framework of labor-based contract grading (LBCG). In a scheme, time and effort ("labor") student spends on an assignment determines credit they receive; component requires students to design projects with clearly-defined goals deliverables which must be satisfied earn credit. LBCG is intended promote agency engagement, provide more equitable given that come wide range prior experiences preparation. illustrate within context upper level physics course, using...
I describe the assessment framework of labor-based contract grading (LBCG). In a scheme, time and effort (“labor”) student spends on an assignment determines credit they receive; component requires students to design projects with clearly defined goals deliverables, which must be satisfied earn credit. LBCG is intended promote agency engagement provide more equitable framework, given that come wide range prior experiences preparation. illustrate within context upper level physics course,...
We report on the results of performing computational gravitational backreaction cosmic string loops taken from a network simulation. The principal effect is to smooth out small-scale structure loops, which we demonstrate by various measures including average loop power spectrum and distribution kink angles loops. Backreaction does lead self-intersections in most cases, but these are typically small. An important discussed prior work rounding off kinks form cusps, find that cusps produced...
While supermassive black-hole (SMBH)-binaries are not the only viable source for low-frequency gravitational wave background (GWB) signal evidenced by most recent pulsar timing array (PTA) data sets, they expected to be likely. Thus, connecting measured PTA GWB spectrum and underlying physics governing demographics dynamics of SMBH-binaries is extremely important. Previously, Gaussian processes (GPs) dense neural networks have been used make such a connection being built as conditional...
We derive a general procedure for calculating the gravitational wave background (GWB) from cosmic string loops whose typical shape evolves over time, as in backreaction. Using results of large-scale study numerical backreaction on Nambu-Goto loops, we construct GWBs backreacted strings range tensions and frequencies cosmological interest, compare them to current upcoming detectors. The are lower than prior predictions by anywhere few percent around 30\%, depending frequency tension question.
A bstract The large number of moduli fields arising in a generic string theory compactification makes complete computation the low energy effective infeasible. common strategy to solve this problem is consider Calabi-Yau manifolds with discrete symmetries, which effectively reduce and make truncated Effective Field Theory possible. In approach, however, couplings (e.g., masses) are left undetermined. present paper we discuss tree-level mass spectrum type-IIB flux compactifications at Large...