arXiv subjects

Hrishikesh Patel

Publications and source records attributed to Hrishikesh Patel.

11 recordsLinked to original sources

arXiv2025

Holographic Consequences of Heterotic String Theory beyond its Supergravity Approximation

In this work, we study the effects of stringy corrections on the low energy effective action derived from heterotic string theory beyond its supergravity approximation. Compactifying the ten dimensional theory with these stringy corrections produces an effective action for a scalar field whose higher derivative term is governed by a single coefficient that depends on the internal volume, average curvature, and flux of the compactification manifold. The higher derivative coupling imported from compactification shifts the Breitenlohner Freedman stability bound by an amount set by the relative strengths of internal flux and curvature, relaxing it in flux dominated vacua and tightening it in curvature dominated ones. Furthermore, we analyze how the stringy corrections shift the scaling dimensions of the dual operators, track the resulting renormalization group flow, and investigate the higher derivative term using a holographic Lee Wick regulator. In holographic superconductors, stringy corrections lower the effective bulk mass and raise the critical temperature when flux dominates, but have the opposite effect when curvature dominates.

hep-th↗

arXiv2024

EMIT- Event-Based Masked Auto Encoding for Irregular Time Series

Irregular time series, where data points are recorded at uneven intervals, are prevalent in healthcare settings, such as emergency wards where vital signs and laboratory results are captured at varying times. This variability, which reflects critical fluctuations in patient health, is essential for informed clinical decision-making. Existing self-supervised learning research on irregular time series often relies on generic pretext tasks like forecasting, which may not fully utilise the signal provided by irregular time series. There is a significant need for specialised pretext tasks designed for the characteristics of irregular time series to enhance model performance and robustness, especially in scenarios with limited data availability. This paper proposes a novel pretraining framework, EMIT, an event-based masking for irregular time series. EMIT focuses on masking-based reconstruction in the latent space, selecting masking points based on the rate of change in the data. This method preserves the natural variability and timing of measurements while enhancing the model's ability to process irregular intervals without losing essential information. Extensive experiments on the MIMIC-III and PhysioNet Challenge datasets demonstrate the superior performance of our event-based masking strategy. The code has been released at https://github.com/hrishi-ds/EMIT.

cs.LG↗

arXiv2024

Estimating Gender Completeness in Wikipedia

Gender imbalance in Wikipedia content is a known challenge which the editor community is actively addressing. The aim of this paper is to provide the Wikipedia community with instruments to estimate the magnitude of the problem for different entity types (also known as classes) in Wikipedia. To this end, we apply class completeness estimation methods based on the gender attribute. Our results show not only which gender for different sub-classes of Person is more prevalent in Wikipedia, but also an idea of how complete the coverage is for difference genders and sub-classes of Person.

cs.CY↗

arXiv2023

$d$-mon: transmon with strong anharmonicity

We propose a novel qubit architecture based on a planar $c$-axis Josephson junction between a thin flake $d$-wave superconductor ($d$SC), such as a high-$T_c$ cuprate Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$, and a conventional $s$-wave superconductor. When operated in the transmon regime the device -- that we call "$d$-mon" -- becomes insensitive to offset charge fluctuations and, importantly, exhibits at the same time energy level spectrum with strong anharmonicity that is widely tunable through the device geometry and applied magnetic flux. Crucially, unlike previous qubit designs based on $d$-wave superconductors the proposed device operates in a regime where quasiparticles are fully gapped and can be therefore expected to achieve long coherence times.

cond-mat.supr-con↗

arXiv2022

Novel setup for detecting short-range anisotropic corrections to gravity

In this paper we argue that, even though there are strong theoretical and empirical reasons to expect a violation of spatial isotropy at short distances, contemporary setups for probing gravitational interactions at short distances have not been configured to measure such spatial anisotropies. We propose a simple modification to the state-of-the-art torsion pendulum design and numerically demonstrate that it suppresses signals due to the large spatially-isotropic component of the gravitational force while maintaining a high sensitivity to short-range spatial anisotropies. We incorporate anisotropy using both Yukawa-type and power-law-type short-distance corrections to gravity. The proposed differential torsion pendulum is shown to be capable of making sensitive measurements of small gravitational anisotropies and the resulting anisotropic torques are largely independent of the details of the underlying short-distance modification to gravity. Thus, if there is an anisotropic modification to gravity, from any theory, in any form of the modified potential, the proposed setup provides a practical means of detecting it.

gr-qc↗

arXiv2021

Construction of Quantum Target Space from World-Sheet States using Quantum State Tomography

In this paper, we will construct the quantum states of target space coordinates from world-sheet states, using quantum state tomography. To perform quantum state tomography of an open string, we will construct suitable quadrature operators. We do this by first defining the quadrature operators in world-sheet, and then using them to construct the quantum target space quadrature operators for an open string. We will connect the quantum target space to classical geometry using coherent string states. We will be using a novel construction based on a string displacement operator to construct these coherent states. The coherent states of the world-sheet will also be used to construct the coherent states in target space.

hep-th↗

arXiv2020

Testing Short Distance Anisotropy in Space

The isotropy of space is not a logical requirement but rather is an empirical question; indeed there is suggestive evidence that universe might be anisotropic. A plausible source of these anisotropies could be quantum gravity corrections. If these corrections happen to be between the electroweak scale and the Planck scale, then these anisotropies can have measurable consequences at short distances and their effects can be measured using ultra sensitive condensed matter systems. We investigate how such anisotropic quantum gravity corrections modify low energy physics through an anisotropic deformation of the Heisenberg algebra. We discuss how such anisotropies might be observed using a scanning tunneling microscope.

gr-qc↗

arXiv2020

Probing Short Gravity using Temporal Lensing

It is known that probing gravity in the submillimeter-micrometer range is difficult due to the relative weakness of the gravitational force. We intend to overcome this challenge by using extreme temporal precision to monitor transient events in a gravitational field. We propose a compressed ultrafast photography system called T-CUP to serve this purpose. We show that the T-CUP's precision of 10 trillion frames per second can allow us to better resolve gravity at short distances. We also show the feasibility of the setup in measuring Yukawa and power-law corrections to gravity which have substantial theoretical motivation.

gr-qc↗

arXiv2020

Compactification, T-Duality and Quantum Erasers

Using T-duality, we will argue that a zero point length exists in the low energy effective field theory of string theory on compactified extra dimensions. Furthermore, if we neglect the oscillator modes, this zero point length would modify low quantum mechanical systems. As this zero length is fixed geometrically, it is important to analyze how it modifies purely quantum mechanical effects. Thus, we will analyze its effects on quantum erasers, because they are based on quantum effects like entanglement. It will be observed that the behavior of these quantum erasers gets modified by this zero point length. As the zero point length is fixed by the radius of compactification, we argue that these results demonstrate a deeper connection between geometry and quantum effects.

hep-th↗

arXiv2019

Tale of tails using rule augmented sequence labeling for event extraction

The problem of event extraction is a relatively difficult task for low resource languages due to the non-availability of sufficient annotated data. Moreover, the task becomes complex for tail (rarely occurring) labels wherein extremely less data is available. In this paper, we present a new dataset (InDEE-2019) in the disaster domain for multiple Indic languages, collected from news websites. Using this dataset, we evaluate several rule-based mechanisms to augment deep learning based models. We formulate our problem of event extraction as a sequence labeling task and perform extensive experiments to study and understand the effectiveness of different approaches. We further show that tail labels can be easily incorporated by creating new rules without the requirement of large annotated data.

cs.IR↗

arXiv2019

Proposed experimental test of Randall-Sundrum Models

The Randall-Sundrum models are expected to modify the short distance behavior of general relativity. In this paper, we will propose an experimental test for this short distance modification due to Randall-Sundrum models. This will be done by analyzing motion of a particle which is moving in spherical gravitational field with a drag force. The position at which the particle stops will be different in general relativity and Randall-Sundrum model. This difference in the distance moved by the particle before stopping can be measured using a Nanoelectromechanical setup. Thus, it is possible to experimentally test Randall-Sundrum models using currently available technology.

gr-qc↗