English
Related papers

Related papers: Saddle Points in the Auxiliary Field Method

200 papers

As a first step to derive the IBM from a microscopic nuclear hamiltonian, we bosonize the pairing hamiltonian in the framework of the path integral formalism respecting both the particle number conservation and the Pauli principle. Special…

Nuclear Theory · Physics 2009-11-10 M. B. Barbaro , A. Molinari , F. Palumbo , M. R. Quaglia

We discuss the factorization and continuity properties of fields in the Euclidean gravitational path integral with higher dimension operators constructed from powers of the Riemann tensor. We construct the boundary terms corresponding to…

High Energy Physics - Theory · Physics 2023-10-04 Patrick Draper , Szilard Farkas , Manthos Karydas

In this paper, we analyze gradient-free methods with one-point feedback for stochastic saddle point problems $\min_{x}\max_{y} \varphi(x, y)$. For non-smooth and smooth cases, we present analysis in a general geometric setup with arbitrary…

Optimization and Control · Mathematics 2022-09-12 Aleksandr Beznosikov , Vasilii Novitskii , Alexander Gasnikov

We consider saddle point problems which objective functions are the average of $n$ strongly convex-concave individual components. Recently, researchers exploit variance reduction methods to solve such problems and achieve linear-convergence…

Machine Learning · Computer Science 2019-09-17 Luo Luo , Cheng Chen , Yujun Li , Guangzeng Xie , Zhihua Zhang

We perform a precision calculation of the effective field theory (EFT) conditional likelihood for large-scale structure (LSS) using the saddle-point expansion method in the presence of primordial non-Gaussianities (PNG). The precision is…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-11 Ji-Yuan Ke , Yun Wang , Ping He

Escaping saddle points is a central research topic in nonconvex optimization. In this paper, we propose a simple gradient-based algorithm such that for a smooth function $f\colon\mathbb{R}^n\to\mathbb{R}$, it outputs an…

Optimization and Control · Mathematics 2021-11-30 Chenyi Zhang , Tongyang Li

Finding index-1 saddle points is crucial for understanding phase transitions. In this work, we propose a simple yet efficient approach, the spring pair method (SPM), to accurately locate saddle points. Without requiring Hessian information,…

Mathematical Physics · Physics 2024-07-08 Gang Cui , Kai Jiang

We compare different non-perturbative methods for calculating the effective action for fermionic systems featuring bosonic bound states (BBS) and spontaneous symmetry breaking (SSB). In a purely fermionic language proceeding into the SSB…

High Energy Physics - Phenomenology · Physics 2007-05-23 Joerg Jaeckel

The notion of the integral over the anticommuting Grassmann variables (nonquantum fermionic fields) seems to be the most powerful tool in order to extract the exact analytic solutions for the 2D Ising models on simple and more complicated…

High Energy Physics - Theory · Physics 2008-02-03 V. N. Plechko

The graded parafermion conformal field theory at level k is a close cousin of the much-studied Z_k parafermion model. Three character formulas for the graded parafermion theory are presented, one bosonic, one fermionic (both previously…

High Energy Physics - Theory · Physics 2007-05-23 J. -F. Fortin , P. Mathieu , S. O. Warnaar

We propose an inexact Uzawa algorithm with two variable relaxation parameters for solving the generalized saddle-point system. The saddle-point problems can be found in a wide class of applications, such as the augmented Lagrangian…

Numerical Analysis · Mathematics 2014-08-26 Kazufumi Ito , Hua Xiang , Jun Zou

In this article we revisit the auxiliary variable method introduced in Smith and kohn (1996) for the fitting of P-th order spline regression models with an unknown number of knot points. We introduce modifications which allow the location…

Methodology · Statistics 2009-11-11 Y. Fan , J. -L Dortet-Bernadet , S. A. Sisson

The use of variational method in functional integral approach is discussed for fermion and boson systems with Coulomb interaction. The formal general expression of thermodynamic potential is obtained by Feynman path integral technique and…

Statistical Mechanics · Physics 2015-06-24 Ilmars Madzhulis , Vilnis Frishfelds

In many problems of quantum chaos the calculation of sums of products of periodic orbit contributions is required. A general method of computation of these sums is proposed for generic integrable models where the summation over periodic…

chao-dyn · Physics 2009-10-31 E. Bogomolny

In this paper we propose three $p$-th order tensor methods for $\mu$-strongly-convex-strongly-concave saddle point problems (SPP). The first method is based on the assumption of $p$-th order smoothness of the objective and it achieves a…

Optimization and Control · Mathematics 2021-04-14 Petr Ostroukhov , Rinat Kamalov , Pavel Dvurechensky , Alexander Gasnikov

A method to perform bosonization of a fermionic theory in (1+1) dimensions in a path integral framework is developed. The method relies exclusively on the path integral property of allowing variable shifts, and does not depend on the…

High Energy Physics - Theory · Physics 2009-10-31 Jan B. Thomassen

We consider (stochastic) convex-concave saddle point (SP) problems with high-dimensional decision variables, arising in various applications including machine learning problems. To contend with the challenges in computing full gradients, we…

Optimization and Control · Mathematics 2025-09-30 Erfan Yazdandoost Hamedani , Afrooz Jalilzadeh , Necdet Serhat Aybat

In this paper a new method for computation of higher order corrections to the saddle point approximation of the Feynman path integral is discussed. The saddle point approximation leads to local Schr\"odinger problems around classical…

chao-dyn · Physics 2008-02-03 Gabor Vattay

Policy gradient (PG) is widely used in reinforcement learning due to its scalability and good performance. In recent years, several variance-reduced PG methods have been proposed with a theoretical guarantee of converging to an approximate…

Machine Learning · Computer Science 2025-10-01 Sadegh Khorasani , Saber Salehkaleybar , Negar Kiyavash , Niao He , Matthias Grossglauser

A general field-theoretical description of many-fermion systems, with or without quenched disorder, is developed. Starting from the Grassmannian action for interacting fermions, we first bosonize the theory by introducing composite matrix…

Strongly Correlated Electrons · Physics 2014-10-13 D. Belitz , T. R. Kirkpatrick