scholarly journals QUANTUM CORNER — TRANSFER MATRIX DMRG

2008 ◽  
Vol 19 (08) ◽  
pp. 1145-1161 ◽  
Author(s):  
ERIK BARTEL ◽  
ANDREAS SCHADSCHNEIDER

We propose a new method for the calculation of thermodynamic properties of one-dimensional quantum systems by combining the TMRG approach with the corner transfer-matrix method. The corner transfer-matrix DMRG method brings reasonable advantage over TMRG for classical systems. We have modified the concept for the calculation of thermal properties of one-dimensional quantum systems. The novel QCTMRG algorithm is implemented and used to study two simple test cases, the classical Ising chain and the isotropic Heisenberg model. In a discussion, the advantages and challenges are illuminated.

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
J. Hutchinson ◽  
J. P. Keating ◽  
F. Mezzadri

We exploit mappings between quantum and classical systems in order to obtain a class of two-dimensional classical systems characterised by long-range interactions and with critical properties equivalent to those of the class of one-dimensional quantum systems treated by the authors in a previous publication. In particular, we use three approaches: the Trotter-Suzuki mapping, the method of coherent states, and a calculation based on commuting the quantum Hamiltonian with the transfer matrix of a classical system. This enables us to establish universality of certain critical phenomena by extension from the results in the companion paper for the classical systems identified.


2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Rodolfo Panerai ◽  
Antonio Pittelli ◽  
Konstantina Polydorou

Abstract We find a one-dimensional protected subsector of $$ \mathcal{N} $$ N = 4 matter theories on a general class of three-dimensional manifolds. By means of equivariant localization we identify a dual quantum mechanics computing BPS correlators of the original model in three dimensions. Specifically, applying the Atiyah-Bott-Berline-Vergne formula to the original action demonstrates that this localizes on a one-dimensional action with support on the fixed-point submanifold of suitable isometries. We first show that our approach reproduces previous results obtained on S3. Then, we apply it to the novel case of S2× S1 and show that the theory localizes on two noninteracting quantum mechanics with disjoint support. We prove that the BPS operators of such models are naturally associated with a noncom- mutative star product, while their correlation functions are essentially topological. Finally, we couple the three-dimensional theory to general $$ \mathcal{N} $$ N = (2, 2) surface defects and extend the localization computation to capture the full partition function and BPS correlators of the mixed-dimensional system.


2021 ◽  
Vol 5 (7) ◽  
pp. 181
Author(s):  
Dibyani Sahu ◽  
Harekrushna Sutar ◽  
Pragyan Senapati ◽  
Rabiranjan Murmu ◽  
Debashis Roy

Graphene has accomplished huge notoriety and interest from the universe of science considering its exceptional mechanical physical and thermal properties. Graphene is an allotrope of carbon having one atom thick size and planar sheets thickly stuffed in a lattice structure resembling a honeycomb structure. Numerous methods to prepare graphene have been created throughout a limited span of time. Due to its fascinating properties, it has found some extensive applications to a wide variety of fields. So, we believe there is a necessity to produce a document of the outstanding methods and some of the novel applications of graphene. This article centres around the strategies to orchestrate graphene and its applications in an attempt to sum up the advancements that has taken place in the research of graphene.


1987 ◽  
Vol 97 ◽  
Author(s):  
Steven A. Sunshine ◽  
Doris Kang ◽  
James A. Ibers

ABSTRACTThe use of A2 Q/Q melts (A - alkali metal, Q - S or Se) for the synthesis of new one-dimensional solid-state materials is found to be of general utility and is illustrated here for the synthesis of K4 Ti3 SI4. Reaction of Ti metal with a K2 S/S melt at 375°C for 50 h affords K4 Ti3 SI4. The structure possesses one-dimensional chains of seven and eightcoordinate Ti atoms with each chain isolated from all others by surrounding K atoms. There are six S-S pairs (dave - 2.069(3) Å) so that the compound is one of TiIV and may be described as K4 [Ti3 (S)2 (S2)6]. Electrical conductivity measurements indicate that this material is a semiconductor.


VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 257-260
Author(s):  
Surinder P. Singh ◽  
Neil Goldsman ◽  
Isaak D. Mayergoyz

The Boltzmann transport equation (BTE) for multiple bands is solved by the spherical harmonic approach. The distribution function is obtained for energies greater than 3 eV. The BTE is solved self consistently with the Poisson equation for a one dimensional npn bipolar junction transistor (BJT). The novel features are: the use of boundary fitted curvilinear grid, and Scharfetter Gummel type discretization of the BTE.


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