arXiv subjects

Sourav Dutta

Publications and source records attributed to Sourav Dutta.

112 records · Page 7Linked to original sources

arXiv2011

Mode-hop-free tuning over 135 GHz of external cavity diode lasers without anti-reflection coating

We report an external cavity diode laser (ECDL), using a diode whose front facet is not antireflection (AR) coated, that has a mode-hop-free (MHF) tuning range greater than 135 GHz. We achieved this using a short external cavity and by simultaneously tuning the internal and external modes of the laser. We find that the precise location of the pivot point of the grating in our laser is less critical than commonly believed. The general applicability of the method, combined with the compact portable mechanical and electronic design, makes it well suited for both research and industrial applications.

physics.atom-ph↗

arXiv2011

Laser spectroscopy of the X 1Σ+ and B 1Π states of the LiRb molecule

We have studied the X 1Σ+ and B 1Π states of 7Li85Rb using Laser Induced Fluorescence (LIF) spectroscopy and Fluorescence Excitation Spectroscopy (FES). We extract molecular constants for levels v" = 0-2 of the X 1Σ+ state and levels v' = 0-20 of the B 1Π state. For the B 1Π state, we have observed rotational perturbations in the e-parity component of the v' = 2 level, and determined the dissociation energy. We discuss implications of our measurements in finding efficient photoassociation pathways for production of ultra-cold ground state LiRb molecules, and their detection via state selective ionization.

physics.atom-ph↗

arXiv2011

Caching Stars in the Sky: A Semantic Caching Approach to Accelerate Skyline Queries

Multi-criteria decision making has been made possible with the advent of skyline queries. However, processing such queries for high dimensional datasets remains a time consuming task. Real-time applications are thus infeasible, especially for non-indexed skyline techniques where the datasets arrive online. In this paper, we propose a caching mechanism that uses the semantics of previous skyline queries to improve the processing time of a new query. In addition to exact queries, utilizing such special semantics allow accelerating related queries. We achieve this by generating partial result sets guaranteed to be in the skyline sets. We also propose an index structure for efficient organization of the cached queries. Experiments on synthetic and real datasets show the effectiveness and scalability of our proposed methods.

cs.DB↗

arXiv2010

Mining Statistically Significant Substrings Based on the Chi-Square Measure

Given the vast reservoirs of data stored worldwide, efficient mining of data from a large information store has emerged as a great challenge. Many databases like that of intrusion detection systems, web-click records, player statistics, texts, proteins etc., store strings or sequences. Searching for an unusual pattern within such long strings of data has emerged as a requirement for diverse applications. Given a string, the problem then is to identify the substrings that differs the most from the expected or normal behavior, i.e., the substrings that are statistically significant. In other words, these substrings are less likely to occur due to chance alone and may point to some interesting information or phenomenon that warrants further exploration. To this end, we use the chi-square measure. We propose two heuristics for retrieving the top-k substrings with the largest chi-square measure. We show that the algorithms outperform other competing algorithms in the runtime, while maintaining a high approximation ratio of more than 0.96.

cs.DB↗