Megha Agarwal | Searcharxiv

arXiv2024

Disorder and non-Hermiticity in Kitaev spin liquids with a Majorana Fermi surface

We study the effect of disorder on Z$_2$ quantum spin liquids with a Majorana Fermi line (respectively surface in three dimensions) and show that depending on the symmetries that are preserved \emph{on average} qualitatively different scenarios will occur. In particular, we identify the relevant non-Hermitian symmetries for which disorder will effectively split the Fermi line into two exceptional lines, with $\Re(E)=0$ states filling the area in between. We demonstrate the different scenarios using both toy models as well as large-scale numerical simulations.

cond-mat.str-el↗

arXiv2017

Detection of Copy-move Image forgery using SVD and Cuckoo Search Algorithm

Copy-move forgery is one of the simple and effective operations to create forged images. Recently, techniques based on singular value decomposition (SVD) are widely used to detect copy-move forgery (CMF). Some approaches based on SVD are most acceptable to detect copy-move forgery but some copy-move forgery detection approaches can not produce satisfactory detection results. Sometimes these approaches may even produce error results. According to our observation, detection result produced using SVD depend highly on those parameters whose values are often determined with experiences. These values are only applicable to a few images, which limit their application. To solve this problem, a novel approach named as copy-move forgery detection using Cuckoo search algorithm (CMFD-CS) is proposed in this paper. CMFD-CS integrates the CS algorithm into SVD. It utilizes the CS algorithm to generate customized parameter values for images, which are used CMFD under block-based framework.

cs.MM↗