Publications (25)
Theoretical study of the spin and charge dynamics of two-leg ladders as probed by resonant inelastic x-ray scattering
Umesh Kumar, Alberto Nocera, Elbio Dagotto +1
Resonant inelastic x-ray scattering (RIXS) has become an important tool for studying elementary excitations in correlated materials. Here, we present a systematic theoretical inves…
Impurity dynamics in a zero-temperature gas
Umesh Kumar, Abhishek Dhar, P. L. Krapivsky
If energy is suddenly released in a localized region of space uniformly filled with identical stationary hard spheres, the outcome is a blast with an asymptotically spherical shock…
Multi-spinon and holon excitations probed by resonant inelastic x-ray scattering on doped one-dimensional antiferromagnets
Umesh Kumar, Alberto Nocera, Elbio Dagotto +1
Resonant inelastic x-ray scattering (RIXS) at the oxygen -edge has recently accessed multi-spinon excitations in the one-dimensional antiferromagnet (1D-AFM) \sco, where four-sp…
Inverse Faraday effect in Mott insulators
Saikat Banerjee, Umesh Kumar, Shi-Zeng Lin
The inverse Faraday effect (IFE), where a static magnetization is induced by circularly polarized light, offers a promising route to ultrafast control of spin states. Here we study…
Invariant measure for the stochastic Cauchy problem driven by a cylindrical Lévy process
Umesh Kumar, Markus Riedle
In this work, we present sufficient conditions for the existence of a stationary solution of an abstract stochastic Cauchy problem driven by an arbitrary cylindrical Lévy process,…
Observation of multiple attractors and diffusive transport in a periodically driven Klein-Gordon chain
Umesh Kumar, Seemant Mishra, Anupam Kundu +1
We consider a Klein-Gordon chain that is periodically driven at one end and has dissipation at one or both boundaries. An interesting numerical observation in a recent study~[arXiv…
Particle-hole asymmetry in the dynamical spin and charge structure factors of the corner-shared one-dimensional cuprates
Shaozhi Li, Alberto Nocera, Umesh Kumar +1
The collective spin and charge excitations of doped cuprates and their relationship to superconductivity are not yet fully understood, particularly in the case of the charge excita…
Neuronal Fluctuations: Learning Rates vs Participating Neurons
Darsh Pareek, Umesh Kumar, Ruthu Rao +1
Deep Neural Networks (DNNs) rely on inherent fluctuations in their internal parameters (weights and biases) to effectively navigate the complex optimization landscape and achieve r…
Softening of excitation in the resonant inelastic x-ray scattering spectra as a signature of Hund's coupling in nickelates
Umesh Kumar, Corey Melnick, Gabriel Kotliar
We investigate the effects of Hund's coupling on the resonant X-ray absorption spectra of the recently discovered family of layered nickelate superconductors. We contrast two scena…
Floquet engineering of Kitaev quantum magnets
Umesh Kumar, Saikat Banerjee, Shi-Zeng Lin
In recent years, there has been an intense search for materials realizing the Kitaev quantum spin liquid model. A number of edge-shared compounds with strong spin-orbit coupling, s…
Three-body bound states in antiferromagnetic spin ladders
Gary Schmiedinghoff, Leanna Müller, Umesh Kumar +2
Stable bound quantum states are ubiquitous in nature. Mostly, they result from the interaction of only pairs of particles, so called two-body interactions, even when large complex…
Predicting Fractionalized Multi-Spin Excitations in Resonant Inelastic X-ray Spectra of Frustrated Spin-1/2 Trimer Chains
Prabhakar, Subhajyoti Pal, Umesh Kumar +2
We theoretically investigate the resonant inelastic X-ray scattering (RIXS) spectra in a quasi-1D chain of weakly coupled frustrated spin-1/2 trimers, as realized in NaCu$_{3…
Unveiling In-Gap States and Majorana Zero Modes in Superconductor-Topological Insulator Bilayer model
Umesh Kumar, Rafal Rechcinski, Tatiana de Picoli +2
Interfaces between topological insulators and superconductors are promising platforms for realizing Majorana zero modes (MZMs) via the superconducting proximity effect. We introduc…
Prostate-VarBench: A Benchmark with Interpretable TabNet Framework for Prostate Cancer Variant Classification
Abraham Francisco Arellano Tavara, Umesh Kumar, Jathurshan Pradeepkumar +1
Variants of Uncertain Significance (VUS) limit the clinical utility of prostate cancer genomics by delaying diagnosis and therapy when evidence for pathogenicity or benignity is in…
Imperfect Graphs from Unitary Matrices -- I
Wesley Lewis, Darsh Pareek, Umesh Kumar +1
Matrix representations of quantum operators are computationally complete but often obscure the structural topology of information flow within a quantum circuit \cite{nielsen2000}.…
Spontaneous fractional Chern insulators in transition metal dichalcogenides Moire superlattices
Heqiu Li, Umesh Kumar, Kai Sun +1
Moir{é} superlattice realized in two-dimensional heterostructures offers an exciting platform to access strongly-correlated electronic states. In this work, we study transition me…
Tunable Multifunction Filter Using Current Conveyor
Manish Kumar, M. C. Srivastava, Umesh Kumar
The paper presents a current tunable multifunction filter using current conveyor. The proposed circuit can be realized as on chip tunable low pass, high pass, band pass and ellipti…
Unraveling higher-order corrections in the spin dynamics of RIXS spectra
Umesh Kumar, Abhishek Nag, Jiemin Li +9
Resonant inelastic x-ray scattering (RIXS) is an evolving tool for investigating spin dynamics of strongly correlated materials, which complements inelastic neutron scattering. Bot…
Current Conveyor Based Multifunction Filter
Manish Kumar, M. C. Srivastava, Umesh Kumar
The paper presents a current conveyor based multifunction filter. The proposed circuit can be realized as low pass, high pass, band pass and elliptical notch filter. The circuit em…
Inducing and controlling superconductivity in Hubbard honeycomb model using an electromagnetic drive
Umesh Kumar, Shi-Zeng Lin
The recent successful experimental observation of quantum anomalous Hall effect in graphene under laser irradiation demonstrates the feasibility of controlling single particle band…
Spectroscopic signatures of next-nearest-neighbor hopping in the charge and spin dynamics of doped one-dimensional antiferromagnets
Umesh Kumar, Gregory Price, Kenneth Stiwinter +3
We study the impact of next-nearest-neighbor (nnn) hopping on the low-energy collective excitations of strongly correlated doped antiferromagnetic cuprate spin chains. Specifically…
Excitations across the equilibrium and photoinduced `hidden' states of magnetoresistive manganites
Shiyu Fan, Feng Jin, Taehun Kim +16
"Hidden" phases, generated using ultrafast laser pulses (few hundred femtoseconds), with properties distinct from thermodynamic equilibrium, are appealing for technologies because…
Theoretical analysis of multi-magnon excitations in resonant inelastic x-ray scattering spectra of two-dimensional antiferromagnets
Subhajyoti Pal, Umesh Kumar, Prabhakar +1
Resonant inelastic x-ray spectroscopy (RIXS) has emerged as an important tool to explore magnetism in two-dimensional (2D) antiferromagnet realized in strongly correlated materials…
NMR based Pharmaco-metabolomics: An efficient and agile tool for therapeutic evaluation of Traditional Herbal Medicines
Dinesh Kumar, Atul Rawat, Durgesh Dubey +4
Traditional Indian (Ayurvedic) and Chinese herbal medicines have been used in the treatment of a variety of diseases for thousands of years because of their natural origin and less…
The stochastic Cauchy problem driven by a cylindrical Levy process
Umesh Kumar, Markus Riedle
In this work, we derive sufficient and necessary conditions for the existence of a weak and mild solution of an abstract stochastic Cauchy problem driven by an arbitrary cylindrica…