24 citations · 30 across the 6 of their papers we have counts for
7 papers
A Landscape of Cosmological Decoherence
S. Shajidul Haque, Bret Underwood
Current observations constrain primordial perturbations to be adiabatic, approximately Gaussian, and nearly-scale invariant. However, a generic mixed state satisfying these constra…
Closing the Cosmographic Hierarchy: Dynamical Attractors from Inflation to Reheating
Seturumane Tema, S. Shajidul Haque, Saurya Das +1
We develop a potential-independent cosmographic framework, in which cosmographic parameters are promoted to dynamical variables within a closed autonomous system. Although the cosm…
Stochastic Krylov Dynamics: Revisiting Operator Growth in Open Quantum Systems
Arpan Bhattacharyya, S. Shajidul Haque, Jeff Murugan +2
In closed quantum systems, Krylov complexity admits a geometric description; operator growth is equivalent to Hamiltonian flow in an emergent phase space whose structure is fixed b…
Inflation is Not Magic
S. Shajidul Haque, Ghadir Jafari, Bret Underwood
Cosmological perturbations generated during inflation exhibit striking quantum features, including entanglement and high circuit complexity. Yet their observational signatures rema…
Universal Early-Time Growth in Quantum Circuit Complexity
S. Shajidul Haque, Ghadir Jafari, Bret Underwood
We show that quantum circuit complexity for the unitary time evolution operator of any time-independent Hamiltonian is bounded by linear growth at early times, independent of any c…
The Early Universe as an Open Quantum System: Complexity and Decoherence
Arpan Bhattacharyya, Suddhasattwa Brahma, S. Shajidul Haque +2
In this work, we extend previous results, demonstrating how complexity in an open quantum system can identify decoherence between two fields, even in the presence of an acceleratin…
Complexity and Operator Growth for Quantum Systems in Dynamic Equilibrium
Cameron Beetar, Nitin Gupta, S. Shajidul Haque +2
Krylov complexity is a measure of operator growth in quantum systems, based on the number of orthogonal basis vectors needed to approximate the time evolution of an operator. In th…