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The Density Matrix Renormalisation Group (DMRG) is an electronic structure method that has recently been applied to ab-initio quantum chemistry. Even at this early stage, it has enabled the solution of many problems that would previously…

Renormalization is one of the basic notions of condensed matter physics. Based on the concept of renormalization, the Landau's {\em Fermi liquid} theory has been able to explain, why despite the presence of Coulomb interactions, the free…

Strongly Correlated Electrons · Physics 2009-05-06 S. A. Jafari

Symplectic unitary representations for the Poincar\'{e} group are studied. The formalism is based on the noncommutative structure of the star-product, and using group theory approach as a guide, a consistent physical theory in phase space…

Mathematical Physics · Physics 2016-03-30 R. G. G. Amorim , S. C. Ulhoa , Edilberto O. Silva

We develop a dynamical approach based on the Schwinger-Keldysh formalism to derive a field-theoretic description of disordered and interacting electron systems. We calculate within this formalism the perturbative RG equations for…

Disordered Systems and Neural Networks · Physics 2009-10-31 Claudio Chamon , Andreas W. W. Ludwig , Chetan Nayak

We show an application of the Wilson Renormalization Group (RG) method to a SU(2 ) gauge field theory in interaction with a massive fermionic doublet. By choosing suitable boundary conditions to the RG equation, i.e. by requiring the…

High Energy Physics - Theory · Physics 2007-05-23 S. Arnone , A. Panza

We analyze the vacuum (topological) angle $\theta$ renormalization for the quantum mechanical model of a particle moving around a ring, where $\theta$ is the magnetic flux through the ring. We construct a renormalization group (RG)…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 S. M. Apenko

We study constraint effective potentials for various strongly interacting $\phi^4$ theories. Renormalization group (RG) equations for these quantities are discussed and a heuristic development of a commonly used RG approximation is…

High Energy Physics - Lattice · Physics 2009-09-25 J. R. Shepard , V. Dmitrašinović , J. A. McNeil

We study the reduced Bogoliubov-Dirac-Fock (BDF) energy which allows to describe relativistic electrons interacting with the Dirac sea, in an external electrostatic potential. The model can be seen as a mean-field approximation of Quantum…

Mathematical Physics · Physics 2009-11-13 Philippe Gravejat , Mathieu Lewin , Eric Sere

The renormalization group plays an essential role in many areas of physics, both conceptually and as a practical tool to determine the long-distance low-energy properties of many systems on the one hand and on the other hand search for…

Statistical Mechanics · Physics 2021-05-10 N. Dupuis , L. Canet , A. Eichhorn , W. Metzner , J. M. Pawlowski , M. Tissier , N. Wschebor

The density-matrix renormalization group (DMRG) applied to transfer matrices allows it to calculate static as well as dynamical properties of one-dimensional quantum systems at finite temperature in the thermodynamic limit. To this end the…

Strongly Correlated Electrons · Physics 2007-12-20 S. Glocke , A. Klümper , J. Sirker

When speaking of the unification of quantum mechanics and relativity, one normally refers to special relativity (SR) or to Einstein general relativity (GR). The Dirac and Klein-Gordon wave equations are an example of unification of quantum…

General Physics · Physics 2012-01-31 Leonardo Chiatti

A modified density matrix renormalization group (DMRG) algorithm is applied to the zigzag spin-1/2 chain with frustrated antiferromagnetic exchange $J_1$, $J_2$ between first and second neighbors. The modified algorithm yields accurate…

Strongly Correlated Electrons · Physics 2015-05-18 Manoranjan Kumar , Zoltan G. Soos , Diptiman Sen , S. Ramasesha

We use the functional renormalization group equation for quantum gravity to construct a non-perturbative flow equation for modified gravity theories of the form $S = \int d^dx \sqrt{g} f(R)$. Based on this equation we show that certain…

High Energy Physics - Theory · Physics 2008-11-26 Pedro F. Machado , Frank Saueressig

We exactly solve the (2+1)-dimensional Dirac equation in a constant magnetic field in the presence of a minimal length. Using a proper ansatz for the wave function, we transform the Dirac Hamiltonian into two 2-dimensional non-relativistic…

High Energy Physics - Theory · Physics 2015-02-12 P. Pedram , M. Amirfakhrian , H. Shababi

It is proposed a formalism of quantification of the electric charges in the Kaluza Klein theory of five dimensions and a explanation of the cause of the variation of the electromagnetic fine-structure constant in cosmological times.There is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Paulo da Costa Moreira

In Dirac's fine-structure formula for the hydrogenlike atoms a critical role is played by the square root of the following expression: the unity minus the square of the product of the atomic number by the fine-structure constant (which is…

General Physics · Physics 2007-05-23 A. Loinger

We present the real-time renormalization group (RTRG) method as a method to describe the stationary state current through generic multi-level quantum dots with a complex setup in nonequilibrium. The employed approach consists of a very…

Strongly Correlated Electrons · Physics 2019-05-28 Carsten J. Lindner , Fabian B. Kugler , Volker Meden , Herbert Schoeller

In the report submitted here, an elementary formula is presented that allows calculation of the fine structure constant, derived on the basis of the unified theory of the electromagnetic and gravitational field elaborated by the author.…

General Physics · Physics 2007-05-23 Jaroslav Pavel

A simplified version of White's Density Matrix Renormalization Group (DMRG) algorithm has been used to find the ground state of the free particle on a tight-binding lattice. We generalize this algorithm to treat the tight-binding particle…

Strongly Correlated Electrons · Physics 2009-10-31 M. A. Martin-Delgado , G. Sierra , R. M. Noack

The use of the equations of motion and meson field redefinitions allows the development of a simplified resonance chiral theory lagrangian: terms including resonance fields and a large number of derivatives can be reduced into corresponding…

High Energy Physics - Phenomenology · Physics 2010-04-28 J. J. Sanz-Cillero