34 research outputs found
Quantum simulation of jet evolution in a medium
Jets provide one of the primary probes of the quark-gluon plasma produced in
ultrarelativistic heavy ion collisions and the cold nuclear matter explored in
deep inelastic scattering experiments. However, despite important developments
in the last years, a description of the real-time evolution of QCD jets inside
a medium is still far from complete. In our previous work, we have explored
quantum technologies as a promising alternative theoretical laboratory to
simulate jet evolution in QCD matter, to overcome inherent technical
difficulties in present calculations. Here, we extend our previous
investigation from the single particle to the multiple particle Fock spaces,
taking into account gluon production. Based on the light-front Hamiltonian
formalism, we construct a digital quantum circuit that tracks the evolution of
a multi-particle jet probe in the presence of a stochastic color background.
Using the quantum simulation algorithm, we show the medium-induced modification
to the jet evolution in both the momentum broadening and gluon production.Comment: 6 pages, 4 figures, Proceeding on 11th International Conference on
Hard and Electromagnetic Probes of High Energy Nuclear Collisions (Hard Probe
2023), 26-31 March 2023, Aschaffenburg, Germany. This proceeding is based on
our recent work, arXiv:2307.0179
Anisotropic flow and the valence quark skeleton of hadrons
We study transverse momentum anisotropies, in particular, the elliptic flow
due to the interference effect sourced by valence quarks in high-energy
hadron-hadron collisions. Our main formula is derived as the high-energy
(eikonal) limit of the impact-parameter dependent cross section in quantum
field theory, which agrees with that in terms of the impact parameter in the
classical picture. As a quantitative assessment of the interference effect, we
calculate in the azimuthal distribution of gluons at a comprehensive
coverage of the impact parameter and the transverse momentum in high-energy
pion-pion collisions. In a broad range of the impact parameter, a sizable
amount of , comparable with that produced due to saturated dense gluons or
final-state interactions, is found to develop. In our calculations, the valence
sector of the pion wave function is obtained numerically from the Basis
Light-Front Quantization, a non-perturbative light-front Hamiltonian approach.
And our formalism is generic and can be applied to other small collision
systems like proton-proton collisions
Solving hadron structures using the basis light-front quantization approach on quantum computers
Quantum computing has demonstrated the potential to revolutionize our
understanding of nuclear, atomic, and molecular structure by obtaining
forefront solutions in non-relativistic quantum many-body theory. In this work,
we show that quantum computing can be used to solve for the structure of
hadrons, governed by strongly-interacting relativistic quantum field theory.
Following our previous work on light unflavored mesons as a relativistic
bound-state problem within the nonperturbative Hamiltonian formalism, we
present the numerical calculations on simulated quantum devices using the basis
light-front quantization (BLFQ) approach. We implement and compare the
variational quantum eigensolver (VQE) and the subspace-search variational
quantum eigensolver (SSVQE) to find the low-lying mass spectrum of the light
meson system and its corresponding light-front wave functions as quantum states
from ideal simulators, noisy simulators, and IBM quantum computers. Based on
obtained quantum states, we evaluate the meson decay constants and parton
distribution functions directly on the quantum circuits. Our calculations on
the quantum computers and simulators are in reasonable agreement with accurate
numerical solutions solved on classical computers when noises are moderately
small, and our overall results are comparable with the available experimental
data.Comment: 20 pages, 8 figure
Quantum simulation of in-medium QCD jets: momentum broadening, gluon production, and entropy growth
Jets provide one of the primary probes of the quark-gluon plasma produced in
ultrarelativistic heavy ion collisions and the cold nuclear matter explored in
deep inelastic scattering experiments. However, despite important developments
in the last years, a description of the real-time evolution of QCD jets inside
a medium is still far from being complete. In our previous work, we have
explored quantum technologies as a promising alternative theoretical laboratory
to simulate jet evolution in QCD matter, to overcome inherent technical
difficulties in present calculations. Here, we extend our previous
investigation from the single particle to the
Fock space, taking into account gluon production. Based
on the light-front Hamiltonian formalism, we construct a digital quantum
circuit that tracks the evolution of a multi-particle jet probe in the presence
of a medium described as a stochastic color field. Studying the momentum
broadening of the jet state, we observe sizable sub-eikonal effects by
comparing to eikonal estimates. We also study the medium-induced modifications
to the gluon emission probability, which exhibit small corrections compared to
the vacuum splitting function. In addition, we study the time evolution of the
von-Neumann entropy associated with the quark component; we find that the
exponential of the entropy grows linearly in time for the bare quark but
super-linearly when taking into account gluon emission.Comment: 16 pages, 12 figure
Comparative study of variations in quantum approximate optimization algorithms for the Traveling Salesman Problem
The Traveling Salesman Problem (TSP) is one of the most often-used NP-Hard
problems in computer science to study the effectiveness of computing models and
hardware platforms. In this regard, it is also heavily used as a vehicle to
study the feasibility of the quantum computing paradigm for this class of
problems. In this paper, we tackle the TSP using the quantum approximate
optimization algorithm (QAOA) approach by formulating it as an optimization
problem. By adopting an improved qubit encoding strategy and a layerwise
learning optimization protocol, we present numerical results obtained from the
gate-based digital quantum simulator, specifically targeting TSP instances with
3, 4, and 5 cities. We focus on the evaluations of three distinctive QAOA mixer
designs, considering their performances in terms of numerical accuracy and
optimization cost. Notably, we find a well-balanced QAOA mixer design exhibits
more promising potential for gate-based simulators and realistic quantum
devices in the long run, an observation further supported by our noise model
simulations. Furthermore, we investigate the sensitivity of the simulations to
the TSP graph. Overall, our simulation results show the digital quantum
simulation of problem-inspired ansatz is a successful candidate for finding
optimal TSP solutions.Comment: 18 pages, 6 figures, 3 table
A novel non‑selective atypical PKC agonist could protect neuronal cell line from A β ‑oligomer induced toxicity by suppressing A β generation
Atypical protein kinase C (aPKCs) serve key functions in embryonic development by regulating apical-basal polarity. Previous studies have shed light on their roles during adulthood, especially in the development of Alzheimer\u27s disease (AD). Although the crystal structure of PKCι has been resolved, an agonist of aPKCs remains to be discovered. In the present study, by using the Discovery Studio program and LibDock methodology, a small molecule library (K66-X4436 KINA Set) of compounds were screened for potential binding to PKCι. Subsequently, the computational docking results were validated using affinity selection-mass spectrometry, before in vitro kinase activity was used to determine the function of the hit compounds. A cell-based model assay that can mimic the pathology of AD was then established and used to assess the function of these hit compounds. As a result, the aPKC agonist Z640 was identified, which could bind to PKCι in silico, in vitro and in this cell-based model. Z640 was further confirmed as a non-selective aPKC agonist that can activate the kinase activity of both PKCι and PKCζ. In the cell-based assay, Z640 was found to protect neuronal cell lines from amyloid-β (Aβ) oligomer-induced cell death by reducing reactive oxygen species production and restore mitochondrial function. In addition, Z640 could reduce Aβ40 generation in a dose-dependent manner and shift amyloid precursor protein processing towards the non-amyloid pathway. To conclude, the present study is the first, to the best of the authors\u27 knowledge to identify an aPKC agonist by combining computer-assisted drug discovery and cell-based assays. The present study also revealed that aPKC agonists have therapeutic potential for the treatment of AD
Trends and Progress in Nuclear and Hadron Physics: A Straight or Winding Road
Quantitative calculations of the properties of hadrons and nuclei, with assessed uncertainties, have emerged as competitive with experimental measurements in a number of major cases. We may well be entering an era where theoretical predictions are critical for experimental progress. Cross-fertilization between the fields of relativistic hadronic structure and non-relativistic nuclear structure is readily apparent. Non-perturbative renormalization methods such as similarity renormalization group and Okubo–Lee–Suzuki schemes as well as many-body methods such as coupled cluster, configuration interaction and lattice simulation methods are now employed and advancing in both major areas of physics. New algorithms to apply these approaches on supercomputers are shared among these areas of physics. The roads to success have intertwined with each community taking the lead at various times in the recent past. We briefly sketch these fascinating paths and comment on some symbiotic relationships. We also overview some recent results from the Hamiltonian basis light-front quantization approach
Effects of Phase-Locking Deficits on Speech Recognition in Older Adults With Presbycusis
Objective: People with presbycusis (PC) often report difficulties in speech recognition, especially under noisy listening conditions. Investigating the PC-related changes in central representations of envelope signals and temporal fine structure (TFS) signals of speech sounds is critical for understanding the mechanism underlying the PC-related deficit in speech recognition. Frequency-following responses (FFRs) to speech stimulation can be used to examine the subcortical encoding of both envelope and TFS speech signals. This study compared FFRs to speech signals between listeners with PC and those with clinically normal hearing (NH) under either quiet or noise-masking conditions.Methods: FFRs to a 170-ms speech syllable /da/ were recorded under either a quiet or noise-masking (with a signal-to-noise ratio (SNR) of 8 dB) condition in 14 older adults with PC and 13 age-matched adults with NH. The envelope (FFRENV) and TFS (FFRTFS) components of FFRs were analyzed separately by adding and subtracting the alternative polarity responses, respectively. Speech recognition in noise was evaluated in each participant.Results: In the quiet condition, compared with the NH group, the PC group exhibited smaller F0 and H3 amplitudes and decreased stimulus-response (S-R) correlation for FFRENV but not for FFRTFS. Both the H2 and H3 amplitudes and the S-R correlation of FFRENV significantly decreased in the noise condition compared with the quiet condition in the NH group but not in the PC group. Moreover, the degree of hearing loss was correlated with noise-induced changes in FFRTFS morphology. Furthermore, the speech-in-noise (SIN) threshold was negatively correlated with the noise-induced change in H2 (for FFRENV) and the S-R correlation for FFRENV in the quiet condition.Conclusion: Audibility affects the subcortical encoding of both envelope and TFS in PC patients. The impaired ability to adjust the balance between the envelope and TFS in the noise condition may be part of the mechanism underlying PC-related deficits in speech recognition in noise. FFRs can predict SIN perception performance