Physically interpretable approximations of many-body spectral functions.

Phys Rev E

Computational Science Initiative, Brookhaven National Laboratory, Upton, New York 11973, USA.

Published: January 2024

The rational function approximation provides a natural and interpretable representation of response functions such as the many-body spectral functions. We apply the vector fitting (VFIT) algorithm to fit a variety of spectral functions calculated from the Holstein model of electron-phonon interactions. We show that the resulting rational functions are highly efficient in their fitting of sharp features in the spectral functions, and could provide a means to infer physically relevant information from a spectral data set. The position of the peaks in the approximated spectral function are determined by the location of poles in the complex plane. In addition, we developed a variant of VFIT that incorporates regularization to improve the quality of fits. With this procedure, we demonstrate it is possible to achieve accurate spectral function fits that vary smoothly as a function of physical conditions.

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.109.015302DOI Listing

Publication Analysis

Top Keywords

spectral functions
16
many-body spectral
8
spectral function
8
spectral
7
functions
6
physically interpretable
4
interpretable approximations
4
approximations many-body
4
functions rational
4
function
4

Similar Publications

Detecting Multipartite Entanglement Patterns Using Single-Particle Green's Functions.

Phys Rev Lett

December 2024

Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Division, Upton, New York 11973, USA.

We present a protocol for detecting multipartite entanglement in itinerant many-body electronic systems using single-particle Green's functions. To achieve this, we first establish a connection between the quantum Fisher information and single-particle Green's functions by constructing a set of witness operators built out of single electron creation and destruction operators in a doubled system. This set of witness operators is indexed by a momentum k.

View Article and Find Full Text PDF

Marine resources are attractive for screening new useful bacteria. From a marine sediment sample, we performed isolation and screening of bacterial strains in search of new bioactive compounds. HPLC and ESI-MS analysis indicated that the new bacterium, Lysinibacillus sp.

View Article and Find Full Text PDF

Aggression is commonly associated with increased experiences of peer rejection and maladaptive social information processing biases throughout development. Little is known about the neural correlates of peer rejection that might underlie social information processing biases, and whether these neural correlates are common or different across early- and mid-adolescents on a continuum of aggression. Using the Cyberball task, we examined mediofrontal theta (4-7 Hz) event-related EEG spectral power during conditions of explicit and ambiguous social exclusion in 117 participants (57 early adolescents, ages 10-12 years, and 60 mid-adolescents, ages 14-16 years).

View Article and Find Full Text PDF

Putting Charge Transfer Degree as a Bridge Connecting Surface-Enhanced Raman Spectroscopy and Photocatalysis.

Angew Chem Int Ed Engl

January 2025

Jilin University, State Key Laboratory of Supramolecular Structure and Materials, 2699 Qianjin Street, 130012, Changchun, CHINA.

To date, few systematic approach has been established for predicting catalytic performance by analyzing the spectral information of molecules adsorbed on photocatalyst surfaces. Effective charge transfer (CT) between the semiconductor photocatalysts and surface-absorbed molecules is essential for enhancing catalytic activity and optimizing light energy utilization. This study aimed to validate the surface-enhanced Raman spectroscopy (SERS) based on the CT enhancement mechanism in investigating the CT process during semiconductor photocatalytic C-C coupling model reactions.

View Article and Find Full Text PDF

Thiophene and pyrrole units are extensively utilized in light-responsive materials and have significantly advanced the field of organic photovoltaics (OPV). This progress has inspired our exploration of photosensitizers (PS) for photodynamic therapy (PDT). Currently, traditional PS face limitations in clinical application, including a restricted variety and narrow applicability.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!