



01630nas a2200133   4500008004100000245009300041210006900134260001400203490000800217520118300225100002101408700003001429856003701459       2022                        eng d00aMana and thermalization: Probing the feasibility of near-Clifford Hamiltonian simulation0 aMana and thermalization Probing the feasibility of nearClifford   c9/28/20220 v1063 a<p>Quantum hydrodynamics is the emergent classical dynamics governing transport of conserved quantities in generic strongly-interacting quantum systems. Recent matrix product operator methods have made simulations of quantum hydrodynamics in 1+1d tractable, but they do not naturally generalize to 2+1d or higher, and they offer limited guidance as to the difficulty of simulations on quantum computers. Near-Clifford simulation algorithms are not limited to one dimension, and future error-corrected quantum computers will likely be bottlenecked by non-Clifford operations. We therefore investigate the non-Clifford resource requirements for simulation of quantum hydrodynamics using ``mana&#39;&#39;, a resource theory of non-Clifford operations. For infinite-temperature starting states we find that the mana of subsystems quickly approaches zero, while for starting states with energy above some threshold the mana approaches a nonzero value. Surprisingly, in each case the finite-time mana is governed by the subsystem entropy, not the thermal state mana; we argue that this is because mana is a sensitive diagnostic of finite-time deviations from canonical typicality.</p>1 aSewell, Troy, J.1 aWhite, Christopher, David  uhttps://arxiv.org/abs/2201.1236701810nas a2200121   4500008004100000245006600041210006600107260001400173520141900187100002101606700002401627856003701651       2021                        eng d00aPreparing Renormalization Group Fixed Points on NISQ Hardware0 aPreparing Renormalization Group Fixed Points on NISQ Hardware  c9/20/20213 a<p>Noisy intermediate-scale quantum (NISQ) hardware is typically limited to low-depth quantum circuits to limit the number of opportunities for introduction of error by unreliable quantum gates. A less-explored alternative approach is to repeatedly apply a quantum channel with a desired quantum state as a stable fixed point. Increased circuit depth can in this case be beneficial rather than harmful due to dissipative self-correction. The quantum channels constructed from MERA circuits can be interpreted in terms of the renormalization group(RG), and their fixed points are RG fixed points, i.e. scale-invariant systems such as conformal field theories. Here, building upon the theoretical proposal of Kim and Swingle, we numerically and experimentally study the robust preparation of the ground state of the critical Ising model using circuits adapted from the work of Evenbly and White. The experimental implementation exhibits self-correction through renormalization seen in the convergence and stability of local observables, and makes essential use of the ability to measure and reset individual qubits afforded by the &quot;quantum CCD&quot; architecture of the Honeywell ion-trap. We also numerically test error mitigation by zero-noise extrapolation schemes specially adapted for renormalization circuits, which are able to outperform typical extrapolation schemes using lower gate overhead.&nbsp;</p>1 aSewell, Troy, J.1 aJordan, Stephen, P.  uhttps://arxiv.org/abs/2109.09787