arXiv subjects

Marina Krstic Marinkovic

Publications and source records attributed to Marina Krstic Marinkovic.

16 recordsLinked to original sources

arXiv2026

Photonic Analog Quantum Simulation of (1+1)-Dimensional $U(1)$ Lattice Gauge Theory with Dynamical Matter

We propose a photonic scheme for analog quantum simulation of a $U(1)$ Lattice Gauge Theory (LGT) with dynamical matter based on the Jaynes-Cummings-Hubbard (JCH) model. Here, an array of interacting cavities in the strong-coupling regime of cavity Quantum Electrodynamics is mapped onto the alternating matter and gauge-field sites of the spin-1/2 Quantum Link Model. In contrast to other analog LGT quantum simulation methods, our approach implements the desired gauge-invariant dynamics through the hopping of polaritonic excitations among the array sites. The hopping is mapped to the gauge theory via precise tuning of polaritonic resonances in individual cavities. Using exact diagonalization, we show that the real-time evolution of the JCH model accurately replicates that of a Quantum Link Model. Finally, we discuss feasible routes to the beyond-classical simulation capability with scalable implementations in photonic and superconducting systems. This provides a novel route towards understanding the real-time dynamics of lattice gauge theories with matter in higher dimensions.

hep-lat↗

arXiv2024

Multigrid low-mode averaging

We develop a generalization of low-mode averaging in which the number of low quark modes of the Dirac operator required for a constant variance reduction can be kept independent of the volume by exploiting their local coherence. Typically in lattice QCD simulations, the benefit of translation averaging quark propagators over the space-time volume is spoiled by large fluctuations introduced by the approximations needed to estimate the average. For quark-line connected diagrams at large separations, most of this additional variance can be efficiently suppressed by the introduction of hierarchical subspaces, thanks to the reduced size of the coarse grid operators that act within the subspaces. In this work, we investigate the contributions to the variance of the isovector vector current correlator with $N_{\mathrm f}=2$ non-perturbatively $\mathrm O(a)$-improved Wilson fermions on lattices approximately of size $L=2,3$ and $4$ $\mathrm {fm}$. The numerical results obtained confirm that the variance decreases as the volume is increased when a multigrid decomposition is used with a fixed number of low modes. While the proposed decomposition can be applied to any quark propagator, it is expected to be especially effective for quark-line connected diagrams at large separations, for example, the isovector contribution to the hadronic vacuum polarization or baryonic correlators.

hep-lat↗

arXiv2024

Adiabatic state preparation for digital quantum simulations of QED in 1 + 1D

Quantum electrodynamics in 1 + 1D (QED2) shares intriguing properties with QCD, including confinement, string breaking, and interesting phase diagram when the non-trivial topological $θ$-term is considered. Its lattice regularization is a commonly used toy model for quantum simulations of gauge theories on near-term quantum devices. In this work, we address algorithms for adiabatic state preparation in digital quantum simulations of QED2. We demonstrate that, for specific choices of parameters, the existing adiabatic procedure leads to level crossing between states of different charge sectors, preventing the correct preparation of the ground state. We further propose a new adiabatic Hamiltonian and verify its efficiency in targeting systems with a nonzero topological $θ$-term and in studying string breaking phenomena.

hep-lat↗

arXiv2024

Antistatic-antistatic $\bar Q \bar Q qq$ potentials for $u$, $d$ and $s$ light quarks from lattice QCD

We report on our ongoing lattice QCD computation of antistatic-antistatic potentials in the presence of two light quarks using the CLS $N_f=2$ gauge configurations and the OpenQ*D codebase. We utilize a set of 16 creation operators, corresponding to 8 sectors characterized by angular momentum and parity quantum numbers for light quarks $qq = (ud - du) / \sqrt{2}$ (isospin $0$), $qq \in \{ uu , (ud + du) / \sqrt{2}, dd \}$ (isospin $1$) and $qq \in \{ us , ds \}$ (isospin $1/2$ and strangeness $-1$). We improve on previous work by considering a large number of off-axis separations of the static antiquarks and by using tree-level improvement. The resulting potentials provide vague indication for one-pion exchange at $\bar Q \bar Q$ separations $r \gtrapprox$ 0.5 fm.

hep-lat↗

arXiv2024

Meron-Cluster Algorithms for Quantum Link Models

State-of-the-art algorithms for simulating fermions coupled to gauge fields often rely on integrating fermion degrees of freedom. While successful in simulating QCD at zero chemical potential, at finite density these approaches are hindered by the sign problem. We discuss the simulation of lattice gauge theories in the Hamiltonian formalism and present a generalized meron-cluster algorithm for the simulation of the $U\left(1\right)$ Quantum Link Model for spin $1/2$. This enables the study of models directly relevant to current quantum simulators and is a promising first step toward constructing new efficient algorithms for more complicated gauge theories.

hep-lat↗

arXiv2024

Towards the Application of Skewed Detailed Balance in Lattice Gauge Theories

State-of-the-art algorithms in lattice gauge theory typically rely heavily on detailed balance, which is an instrumental tool to prove the correct convergence of the Markov Chain Monte Carlo Algorithm. In this work, we investigate an alternative to detailed balance, skewed detailed balance, and the prospects of alleviating the topological freezing problem by studying the one-dimensional $O\left(2\right)$ model.

hep-lat↗

arXiv2024

A qubit regularization of asymptotic freedom without fine-tuning

Other than the commonly used Wilson's regularization of quantum field theories (QFTs), there is a growing interest in regularizations that explore lattice models with a strictly finite local Hilbert space, in anticipation of the upcoming era of quantum simulations of QFTs. A notable example is Euclidean qubit regularization, which provides a natural way to recover continuum QFTs that emerge via infrared fixed points of lattice theories. Can such regularizations also capture the physics of ultraviolet fixed points? We present a novel regularization of the asymptotically free massive continuum QFT that emerges at the Berezenski-Kosterlitz-Thouless (BKT) transition through a hard core loop-gas model, discussing the advantages this model provides compared to traditional regularizations. In particular, we demonstrate that without the need for fine-tuning, it can reproduce the universal step-scaling function of the classical lattice XY model in the massive phase as we approach the phase transition.

hep-lat↗

arXiv2023

Antistatic-antistatic-light-light potentials from lattice QCD

We present results for tetraquark potentials of two static anti-quarks $\bar b \bar b$ in the presence of two light quarks $u$ and/or $d$. We improve on existing results by computing the static potential also for off-axis separations, which increases the number of data points significantly. Moreover, we compute for the first time $\bar b \bar b u s$ potentials.

hep-lat↗

arXiv2023

Singly-excited resonant open quantum system Tavis-Cummings model with quantum circuit mapping

Tavis-Cummings (TC) cavity quantum electrodynamical effects, describing the interaction of $N$ atoms with an optical resonator, are at the core of atomic, optical and solid state physics. The full numerical simulation of TC dynamics scales exponentially with the number of atoms. By restricting the open quantum system to a single excitation, typical of experimental realizations in quantum optics, we analytically solve the TC model with an arbitrary number of atoms with linear complexity. This solution allows us to devise the Quantum Mapping Algorithm of Resonator Interaction with $N$ Atoms (Q-MARINA), an intuitive TC mapping to a quantum circuit with linear space and time scaling, whose $N+1$ qubits represent atoms and a lossy cavity, while the dynamics is encoded through $2N$ entangling gates. Finally, we benchmark the robustness of the algorithm on a quantum simulator and superconducting quantum processors against the quantum master equation solution on a classical computer.

quant-ph↗

arXiv2022

Symplectic quantization of multi-field Generalized Proca electrodynamics

We explicitly carry out the symplectic quantization of a family of multi-field Generalized Proca (GP) electrodynamics theories. In the process, we provide an independent derivation of the so-called secondary constraint enforcing relations -- consistency conditions that significantly restrict the allowed interactions in multi-field settings already at the classical level. Additionally, we unveil the existence of quantum consistency conditions, which apply in both single- and multi-field GP scenarios. Our newly found conditions imply that not all classically well-defined (multi-)GP theories are amenable to quantization. The extension of our results to the most general multi-GP class is conceptually straightforward, albeit algebraically cumbersome.

hep-th↗

arXiv2021

Three-dimensional Gross-Neveu model with two flavors of staggered fermions

We introduce a strongly interacting lattice field theory model containing two flavors of massless staggered fermions with two kinds of interactions: (1) a lattice current-current interaction, and (2) an on-site four-fermion interaction. At weak couplings, we expect a massless fermion phase since our interactions become irrelevant at long distances. At strong couplings, based on previous studies, we argue that our lattice model contains two different massive fermion phases with different mechanisms of fermion mass generation. In one phase, fermions become massive through Spontaneous Symmetry Breaking (SSB) via the formation of a fermion bilinear condensate. In the other phase, fermion mass arises through a more exotic mechanism without the formation of any fermion bilinear condensate. Our lattice model is free of sign problems and can be studied using the fermion bag algorithm. The longer term goal here is to study both these mass generation phenomena in a single model and understand how different phases come together.

hep-lat↗

arXiv2019

Exploring the tension between nature and the Standard Model: the muon g-2

Anomalous magnetic moment of the muon (muon g-2) is one of the most precisely measured quantities in particle physics. At the same time, it can be evaluated in the Standard Model with an unprecedented accuracy. The Muon g-2 experiment at Fermilab has started the major data collection and the aimed four-fold increase in precision will shed light on the current discrepancy between the theory prediction and the measured value. This renders a comparable improvement of the precision in the SM theory an essential ingredient in order to fully exploit the expected increase of precision in experimental results. For all these reasons, the muon g-2 is considered to be a great testing ground for new physics. Hadronic contributions are the dominant sources of uncertainty in the theoretical prediction of the muon g-2. A reciprocal effort to a precise determination of the leading hadronic contribution to the muon g-2 using lattice gauge theories is a direct measurement of the hadronic contributions to the running of the fine structure constant recently proposed by the MUonE experiment. A hybrid strategy including both experimental and lattice data sets is expected to give an independent check of the dispersive results from $e^+e^-$ annihilation, which dominate the current world average.

hep-lat↗

arXiv2019

openQ*D code: a versatile tool for QCD+QED simulations

We present the open-source package openQ*D-1.0, which has been primarily, but not uniquely, designed to perform lattice simulations of QCD+QED and QCD, with and without C* boundary conditions, and O(a) improved Wilson fermions. The use of C* boundary conditions in the spatial direction allows for a local and gauge-invariant formulation of QCD+QED in finite volume, and provides a theoretically clean setup to calculate isospin-breaking and radiative corrections to hadronic observables from first principles. The openQ*D code is based on openQCD-1.6 and NSPT-1.4. In particular it inherits from openQCD-1.6 several core features, e.g. the highly optimized Dirac operator, the locally deflated solver, the frequency splitting for the RHMC, or the 4th order OMF integrator.

hep-lat↗

arXiv2017

Lattice calculations and the muon anomalous magnetic moment

Anomalous magnetic moment of the muon, $a_μ=(g_μ-2)/2$, is one of the most precisely measured quantities in particle physics and it provides a stringent test of the Standard Model. The planned improvements of the experimental precision at Fermilab and at J-PARC propel further reduction of the theoretical uncertainty of $a_μ$. The hope is that the efforts on both sides will help resolve the current discrepancy between the experimental measurement of $a_μ$ and its theoretical prediction, and potentially gain insight into new physics. The dominant sources of the uncertainty in the theoretical prediction of $a_μ$ are the errors of the hadronic contributions. I will discuss recent progress on determination of hadronic contributions to $a_μ$ from lattice calculations.

hep-lat↗

arXiv2017

Platform independent profiling of a QCD code

The supercomputing platforms available for high performance computing based research evolve at a great rate. However, this rapid development of novel technologies requires constant adaptations and optimizations of the existing codes for each new machine architecture. In such context, minimizing time of efficiently porting the code on a new platform is of crucial importance. A possible solution for this common challenge is to use simulations of the application that can assist in detecting performance bottlenecks. Due to prohibitive costs of classical cycle-accurate simulators, coarse-grain simulations are more suitable for large parallel and distributed systems. We present a procedure of implementing the profiling for openQCD code [1] through simulation, which will enable the global reduction of the cost of profiling and optimizing this code commonly used in the lattice QCD community. Our approach is based on well-known SimGrid simulator [2], which allows for fast and accurate performance predictions of HPC codes. Additionally, accurate estimations of the program behavior on some future machines, not yet accessible to us, are anticipated.

hep-lat↗

arXiv2016

An exploratory study of heavy domain wall fermions on the lattice

We report on an exploratory study of domain wall fermions (DWF) as a lattice regularisation for heavy quarks. Within the framework of quenched QCD with the tree-level improved Symanzik gauge action we identify the DWF parameters which minimise discretisation effects. We find the corresponding effective 4$d$ overlap operator to be exponentially local, independent of the quark mass. We determine a maximum bare heavy quark mass of $am_h\approx 0.4$, below which the approximate chiral symmetry and O(a)-improvement of DWF are sustained. This threshold appears to be largely independent of the lattice spacing. Based on these findings, we carried out a detailed scaling study for the heavy-strange meson dispersion relation and decay constant on four ensembles with lattice spacings in the range $2.0-5.7\,\mathrm{GeV}$. We observe very mild $a^2$ scaling towards the continuum limit. Our findings establish a sound basis for heavy DWF in dynamical simulations of lattice QCD with relevance to Standard Model phenomenology.

hep-lat↗