Certain Feynman integrals are associated to Calabi-Yau geometries. We demonstrate how these integrals can be computed with the method of differential equations. The four-loop equal-mass banana integral is the simplest Feynman integral whose geometry is a nontrivial Calabi-Yau manifold. We show that its differential equation can be cast into an ϵ-factorized form. This allows us to obtain the solution to any desired order in the dimensional regularization parameter ϵ. The method generalizes to other Calabi-Yau Feynman integrals. Our calculation also shows that the four-loop banana integral is only minimally more complicated than the corresponding Feynman integrals at two or three loops.
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http://dx.doi.org/10.1103/PhysRevLett.130.101601 | DOI Listing |
J Chem Phys
December 2024
Institut für Thermodynamik, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg, Holstenhofweg 85, 22043 Hamburg, Germany.
We apply the methodology of Lustig, with which rigorous expressions for all thermodynamic properties can be derived in any statistical ensemble, to derive expressions for the calculation of thermodynamic properties in the path integral formulation of the quantum-mechanical isobaric-isothermal (NpT) ensemble. With the derived expressions, thermodynamic properties such as the density, speed of sound, or Joule-Thomson coefficient can be calculated in path integral Monte Carlo simulations, fully incorporating quantum effects without uncontrolled approximations within the well-known isomorphism between the quantum-mechanical partition function and a classical system of ring polymers. The derived expressions are verified by simulations of supercritical helium above the vapor-liquid critical point at selected state points using recent highly accurate ab initio potentials for pairwise and nonadditive three-body interactions.
View Article and Find Full Text PDFSci Rep
October 2024
MEMI lab, AI Graduate School, Gwangju Institute of Science and Technology, Gwangju, South Korea.
In this paper, we propose employing electron scattering to realize unitary quantum gates that are controlled by three qubits. Using Feynman's rules, we find an expression for the transition amplitude for scattering from an external electromagnetic source. In this context, the scattering amplitude is modeled as a unitary gate whose state can be regulated.
View Article and Find Full Text PDFJ Vis Exp
October 2024
School of Integrative Engineering, Chung-Ang University; Feynman Institute of Technology, Nanomedicine Corporation;
Antibiotics are currently the most used antibacterial treatment for killing bacteria. However, bacteria develop resistance when continually overexposed to antibiotics. Developing antimicrobial agents that can replace existing antibiotics is essential because antibiotic-resistant bacteria have resistance mechanisms for all current antibiotics and can promote nosocomial infections.
View Article and Find Full Text PDFJ Chem Phys
October 2024
College of Physics and Electronic Engineering, and Center for Computational Sciences, Sichuan Normal University, Chengdu 610068, China.
Developing numerical exact solvers for open quantum systems is a challenging task due to the non-perturbative and non-Markovian nature when coupling to structured environments. The Feynman-Vernon influence functional approach is a powerful analytical tool to study the dynamics of open quantum systems. Numerical treatments of the influence functional including the quasi-adiabatic propagator technique and the tensor-network-based time-evolving matrix product operator method have proven to be efficient in studying open quantum systems with bosonic environments.
View Article and Find Full Text PDFJ Chem Theory Comput
November 2024
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
The presence of loss mechanisms governed by empirical timescales can profoundly affect the dynamics in molecular systems, leading to changes in their spectra. However, incorporation of these effects along with the system's interaction with the thermal dissipative environments proves to be challenging. In this work, we demonstrate the possibility of utilizing the recently developed path integral Lindblad dynamics (PILD) method to study the linear spectra of molecular aggregates.
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