



@article {3358,
	title = {Non-equilibrium critical scaling and universality in a quantum simulator},
	year = {2023},
	month = {9/19/2023},
	abstract = {<p>Universality and scaling laws are hallmarks of equilibrium phase transitions and critical phenomena. However, extending these concepts to non-equilibrium systems is an outstanding challenge. Despite recent progress in the study of dynamical phases, the universality classes and scaling laws for non-equilibrium phenomena are far less understood than those in equilibrium. In this work, using a trapped-ion quantum simulator with single-ion resolution, we investigate the non-equilibrium nature of critical fluctuations following a quantum quench to the critical point. We probe the scaling of spin fluctuations after a series of quenches to the critical Hamiltonian of a long-range Ising model. With systems of up to 50 spins, we show that the amplitude and timescale of the post-quench fluctuations scale with system size with distinct universal critical exponents. While a generic quench can lead to thermal critical behaviour, we find that a second quench from one critical state to another (i.e. a double quench) results in critical behaviour that does not have an equilibrium counterpart. Our results demonstrate the ability of quantum simulators to explore universal scaling beyond the equilibrium paradigm.</p>},
	url = {https://arxiv.org/abs/2309.10856},
	author = {A. De and P. Cook and K. Collins and W. Morong and D. Paz and P. Titum and G. Pagano and Alexey V. Gorshkov and M. Maghrebi and C. Monroe}
}
@article {2409,
	title = {Floquet engineering of optical lattices with spatial features and periodicity below the diffraction limit},
	year = {2019},
	month = {06/18/2019},
	abstract = {<p>Floquet engineering or coherent time periodic driving of quantum systems has been successfully used to synthesize Hamiltonians with novel properties. In ultracold atomic systems, this has led to experimental realizations of artificial gauge fields, topological band structures, and observation of dynamical localization, to name just a few. Here we present a Floquet-based framework to stroboscopically engineer Hamiltonians with spatial features and periodicity below the diffraction limit of light used to create them by time-averaging over various configurations of a 1D optical Kronig-Penney (KP) lattice. The KP potential is a lattice of narrow subwavelength barriers spaced by half the optical wavelength (λ/2) and arises from the non-linear optical response of the atomic dark state. Stroboscopic control over the strength and position of this lattice requires time-dependent adiabatic manipulation of the dark state spin composition. We investigate adiabaticity requirements and shape our time-dependent light fields to respect the requirements. We apply this framework to show that a λ/4-spaced lattice can be synthesized using realistic experimental parameters as an example, discuss mechanisms that limit lifetimes in these lattices, explore candidate systems and their limitations, and treat adiabatic loading into the ground band of these lattices.</p>},
	url = {https://arxiv.org/abs/1906.07646},
	author = {S. Subhankar and P. Bienias and P. Titum and T-C. Tsui and Y. Wang and Alexey V. Gorshkov and S. L. Rolston and J. V. Porto}
}
