Wed·Oct 12, 2022Wednesday·October 12, 2022

1. 01*

   Quantum chaos in supersymmetric Yang-Mills-like model: equation of state, entanglement, and spectral form-factors

   Pavel Buividovich🇬🇧

   We analyze in detail a sharp transition between the low-energy, low-dimensional eigenstates and the high-energy chaotic bulk of the spectrum for a simple supersymmetric quantum-mechanical model with Hamiltonian ${\hat{H}}_S=\left({\hat{p}}_1^2+{\hat{p}}_2^2+{\hat{x}}_1^2{\hat{x}}_2^2\right)\otimes I+{\hat{x}}_1\otimes {\sigma }_1+{\hat{x}}_2\otimes {\sigma }_3$, which mimics the structure of the Banks-Fischler-Susskind-Stanford (BFSS) matrix model, the spatially compactified $\mathcal{N}=1$ super-Yang-Mills theory. We conjecture that this transition might be similar to the transition between the $D0$-brane and $M$-theory regimes in the BFSS model, and find that it does not lead to irregularities in the thermodynamic equation of state. We demonstrate that real-time spectral form-factor for our supersymmetric model exhibits the ``ramp'' behavior typical for quantum chaos. We also analyze the entanglement entropy and the spectrum of the reduced density matrix of the eigenstates of ${\hat{H}}_S$, considering one of the bosonic degrees of freedom as a subsystem. The entanglement entropy of low-energy eigenstates appears to be practically energy-independent. Exactly at the onset of random-matrix-type level spacing fluctuations, this behavior rapidly changes into a steady growth of entanglement with energy. We demonstrate that the spectrum of the reduced density matrix also exhibits universal level-spacing fluctuations towards its higher end, even for the ground state of the supersymmetric model. Thus even the regularly spaced, non-chaotic eigenstates contain some information about semi-classical chaotic dynamics at high energies.

   hep-lathep-thPoS(2023)·6 citations
2. 02*

   Lattice QCD studies on decuplet baryons as meson-baryon bound states in the HAL QCD method

   Kotaro Murakami🇯🇵 · Yutaro Akahoshi🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Kenji Sasaki🇯🇵

   We study decuplet baryons from meson-baryon interactions in lattice QCD, in particular, $\Delta$ and $\Omega$ baryons from P-wave $I=3/2$ $N\pi$ and $I=0$ $\Xi \bar{K}$ interactions, respectively. Interaction potentials are calculated in the HAL QCD method using 3-quark-type source operators at $m_{\pi }\approx 410\text{MeV}$ and $m_K\approx 635\text{MeV}$, where $\Delta$ as well as $\Omega$ baryons are stable. We use the conventional stochastic estimate of all-to-all propagators combined with the all-mode averaging to reduce statistical fluctuations. We have found that the $\Xi \bar{K}$ system has a weaker attraction than the $N\pi$ system while the binding energy from the threshold is larger for $\Omega$ than $\Delta$. This suggests that an inequality $m_N+m_{\pi }-m_{\Delta }<m_{\Xi }+m_{\bar{K}}-m_{\Omega }$ comes mainly from a smaller spatial size of a $\Xi \bar{K}$ bound state due to a larger reduced mass, rather than its interaction. Root-mean-square distances of bound states in both systems are small, indicating that $\Delta$ and $\Omega$ are tightly bound states and thus can be regarded qualitatively as composite states of 3 quarks. Results of binding energies agree with those obtained from temporal 2-point functions within large systematic errors, which arise dominantly from the lattice artifact at short distances.

   hep-lathep-phnucl-thPTEP(2023)·7 citations
3. 03*

   Improving efficiency of the path optimization method for a gauge theory

   Yusuke Namekawa🇯🇵 · Kouji Kashiwa🇯🇵 · Hidefumi Matsuda🇯🇵 · Akira Ohnishi🇯🇵 · Hayato Takase

   We investigate efficiency of a gauge-covariant neural network and an approximation of the Jacobian in optimizing the complexified integration path toward evading the sign problem in lattice field theories. For the construction of the complexified integration path, we employ the path optimization method. The $2$-dimensional $\text{U}(1)$ gauge theory with the complex gauge coupling constant is used as a laboratory to evaluate the efficiency. It is found that the gauge-covariant neural network, which is composed of the Stout-like smearing, can enhance the average phase factor, as the gauge-invariant input does. For the approximation of the Jacobian, we test the most drastic case in which we perfectly drop the Jacobian during the learning process. It reduces the numerical cost of the Jacobian calculation from $\mathcal{O}(N^3)$ to $\mathcal{O}(1)$, where $N$ means the number of degrees of freedom of the theory. The path optimization using this Jacobian approximation still enhances the average phase factor at expense of a slight increase of the statistical error.

   hep-latcond-mat.dis-nnPRD(2023)·11 citations
4. 04*

   The Sphaleron Rate from 4D Euclidean Lattices

   Marc Barroso Mancha🇩🇪 · Guy D. Moore🇩🇪

   We develop a new method to determine thermal activation rates, such as for bubble nucleation, topology change, \textsl{etc.}, using 4-dimensional Euclidean methods. This allows nonperturbative study on the lattice. We then investigate the strong sphaleron rate in pure-glue QCD at temperatures between 1.3 $\text{Tc}$ and 1000 $T_{\mathrm{c}}$, making contact with previous results but extending them down close to the critical temperature. The extension to full QCD will be straightforward. Limitations of the proposal (the inability to compute a certain dynamical prefactor, puzzling large-volume behavior, and the inability to treat temperatures $T<1.3T_{\mathrm{c}}$) are also discussed.

   hep-lathep-phnucl-thJHEP(2023)·29 citations
5. 05*

   QED on the lattice and numerical perturbative computation of $g-2$

   Ryuichiro Kitano🇯🇵 · Hiromasa Takaura🇯🇵

   We compute the electron $g$ factor to the $\mathcal{O}({\alpha }^5)$ order on the lattice in quenched QED. We first study finite volume corrections in various IR regularization methods to discuss which regularization is optimal for our purpose. We find that in QED${}_L$ the finite volume correction to the effective mass can have different parametric dependences depending on the size of Euclidean time $t$ and match the `naive on-shell result' only at very large $t$ region, $t\gg L$. We adopt finite photon mass regularization to suppress finite volume effects exponentially and also discuss our strategy for selecting simulation parameters and the order of extrapolations to efficiently obtain the $g$ factor. We perform lattice simulation using small lattices to test feasibility of our calculation strategy. This study can be regarded as an intermediate step toward giving the five-loop coefficient independently of the preceding studies.

   hep-lathep-phPTEP(2023)·5 citations
6. 06*

   State Preparation in the Heisenberg Model through Adiabatic Spiraling

   Anthony N. Ciavarella🇺🇸 · Stephan Caspar🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸

   An adiabatic state preparation technique, called the adiabatic spiral, is proposed for the Heisenberg model. This technique is suitable for implementation on a number of quantum simulation platforms such as Rydberg atoms, trapped ions, or superconducting qubits. Classical simulations of small systems suggest that it can be successfully implemented in the near future. A comparison to Trotterized time evolution is performed and it is shown that the adiabatic spiral is able to outperform Trotterized adiabatics.

   ↳ quant-phcond-mat.quant-gashep-latnucl-thQuantum(2023)·17 citations
7. 07*

   Quantum Fibrations: quantum computation on an arbitrary topological space

   Kazuki Ikeda🇨🇦

   Using von Neumann algebras, we extend the theory of quantum computation on a graph to a theory of computation on an arbitrary topological space.

   ↳ math.OAhep-lathep-thmath-ph+2Acta Math.Sin.Engl.Ser.(2024)·1 citation
8. 08*

   Perturbative boundaries of quantum computing: real-time evolution for digitized lambda phi^4 lattice models

   Robert Maxton🇺🇸 · Yannick Meurice🇺🇸

   The real time evolution of quantum field theory models can be calculated order by order in perturbation theory. For $\lambda {\varphi }^4$ models, the perturbative series have a zero radius of convergence which in part motivated the design of digitized versions suitable for quantum computing. In agreement with general arguments suggesting that a large field cutoff modifies Dyson's reasoning and improves convergence properties, we show that the harmonic digitizations of $\lambda {\varphi }^4$ lattice field theories lead to weak coupling expansions with a finite radius of convergence. Similar convergence properties are found for strong coupling expansions. We compare the resources needed to calculate the real-time evolution of the digitized models with perturbative expansions to those needed to do so with universal quantum computers. Unless new approximate methods can be designed to calculate long perturbative series for large systems efficiently, it appears that the use of universal quantum computers with digitizations involving a few qubits per site has the potential for more efficient calculations of the real-time evolution for large systems at intermediate coupling.

   ↳ quant-phcond-mat.stat-mechhep-lathep-thPRD(2023)·7 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.