Mon·Oct 11, 2021Monday·October 11, 2021

1. 01*

   Higher order quantization conditions for two spinless particles

   Frank X. Lee🇺🇸 · Andrei Alexandru🇺🇸 · Ruairí Brett🇺🇸

   Lattice QCD calculations of scattering phaseshifts and resonance parameters in the two-body sector are becoming precision studies. Early calculations employed Lüscher's formula for extracting these quantities at lowest order. As the calculations become more ambitious, higher-order relations are required. In this study we derive higher-order quantization conditions and introduce a method to transparently cross-check our results. This is an important step given the involved derivations of these formulae. We derive quantization conditions up to $\ell =5$ partial waves in both cubic and elongated geometries, and for states with zero and non-zero total momentum. All 45 quantization conditions we include here (22 in cubic box, 23 in elongated box) pass our cross-check test.

   hep-latPoS(2022)·2 citations
2. 02*

   Critical Behaviour in the Single Flavor Planar Thirring Model

   Simon Hands🇬🇧 · Michele Mesiti🇬🇧 · Jude Worthy🇬🇧

   We report results of simulations of the $2+1d$ Thirring model with $N$ fermion flavors, defined on a lattice using domain wall fermions. This approach is devised to respect as far as possible the underlying U($2N$) symmetry of the continuum model, expected to be recovered in the limit wall separation $L_s\to \infty$. For $N=1$ there is a symmetry-breaking phase transition associated with bilinear condensation at strong fermion self-interaction, which is a plausible location for a quantum critical point. Fits to a renormalisation group-inspired equation of state yield critical exponents distinct from those obtained using a version of the model defined using staggered fermions.

   hep-latcond-mat.str-elhep-thPoS(2022)·2 citations
3. 03*

   Towards Quantum Simulations in Particle Physics and Beyond on Noisy Intermediate-Scale Quantum Devices

   Lena Funcke🇨🇦 · Tobias Hartung🇬🇧 · Karl Jansen🇩🇪 · Stefan Kühn🇨🇾 · Manuel Schneider🇩🇪 · Paolo Stornati🇩🇪 · Xiaoyang Wang🇨🇳

   We review two algorithmic advances that bring us closer to reliable quantum simulations of model systems in high energy physics and beyond on noisy intermediate-scale quantum (NISQ) devices. The first method is the dimensional expressivity analysis of quantum circuits, which allows for constructing minimal but maximally expressive quantum circuits. The second method is an efficient mitigation of readout errors on quantum devices. Both methods can lead to significant improvements in quantum simulations, e.g., when variational quantum eigensolvers are used.

   ↳ quant-phhep-latPhil.Trans.A.Math.Phys.Eng.Sci.(2021)·30 citations
4. 04*

   Fast emulation of quantum three-body scattering

   Xilin Zhang🇺🇸 · R.J. Furnstahl🇺🇸

   We develop a class of emulators for solving quantum three-body scattering problems. They are based on combining the variational method for scattering observables and the recently proposed eigenvector continuation concept. The emulators are first trained by the exact scattering solutions of the governing Hamiltonian at a small number of points in its parameter space, and then employed to make interpolations and extrapolations in that space. Through a schematic nuclear-physics model with finite-range two and three-body interactions, we demonstrate the emulators to be extremely accurate and efficient. The computing time for emulation is on the scale of milliseconds (on a laptop), with relative errors ranging from $10^{-13}$ to $10^{-4}$ depending on the case. The emulators also require little memory. We argue that these emulators can be generalized to even more challenging scattering problems. Furthermore, this general strategy may be applicable for building the same type of emulators in other fields, wherever variational methods can be developed for evaluating physical models.

   ↳ nucl-thhep-latphysics.atom-phphysics.comp-ph+1PRC(2022)·45 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.