Nuclear Theory·nucl-th

Tuesday·December 12, 2023

13 papers—5 primary·8 cross-listed

06
Quantum Algorithms for Simulating Nuclear Effective Field Theories
James D. Watson🇺🇸 · Jacob Bringewatt🇺🇸 · Alexander F. Shaw🇺🇸 · Andrew M. Childs🇺🇸 · Alexey V. Gorshkov🇺🇸 · Zohreh Davoudi🇺🇸
Quantum computers offer the potential to simulate nuclear processes that are classically intractable. With the goal of understanding the necessary quantum resources to realize this potential, we employ state-of-the-art Hamiltonian-simulation methods, and conduct a thorough algorithmic analysis, to estimate the qubit and gate costs to simulate low-energy effective field theories (EFTs) of nuclear physics. Within the framework of nuclear lattice EFT, we obtain simulation costs for the leading-order pionless and pionful EFTs. For the latter, we consider both static pions represented by a one-pion-exchange potential between the nucleons, and dynamical pions represented by relativistic bosonic fields coupled to non-relativistic nucleons. Within these models, we examine the resource costs for the tasks of time evolution and energy estimation for physically relevant scales. We account for model errors associated with truncating either long-range interactions in the one-pion-exchange EFT or the pionic Hilbert space in the dynamical-pion EFT, and for algorithmic errors associated with product-formula approximations and quantum phase estimation. We find that the pionless EFT is the least costly to simulate, followed by the one-pion-exchange theory, then the dynamical-pion theory. We demonstrate how symmetries of the low-energy nuclear Hamiltonians can be utilized to obtain tighter error bounds. By retaining the locality of nucleonic interactions when mapped to qubits, we achieve reduced circuit depth and substantial parallelization. In the process, we develop new methods to bound the algorithmic error for classes of fermionic number-preserving Hamiltonians, and obtain tighter Trotter error bounds by explicitly computing nested commutators of Hamiltonian terms. Compared to previous estimates for the pionless EFT, our results represent an improvement by several orders of magnitude.
↳ quant-phhep-lathep-phnucl-th40 citations
07
Production of the $X (4014)$ as the spin-2 partner of $X (3872)$ in $e^{+} e^{-}$ collisions
Pan-Pan Shi🇨🇳 · Vadim Baru🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Alexey Nefediev🇸🇮
In 2021, the Belle collaboration reported the first observation of a new structure in the $ψ (2 S) γ$ final state produced in the two-photon fusion process. In the hadronic molecule picture, this new structure can be associated with the shallow isoscalar $D^{*} D ˉ^{*}$ bound state and as such is an excellent candidate for the spin-2 partner of the $X (3872)$ with the quantum numbers $J^{P C} = 2^{++}$ conventionally named $X_{2}$ . In this work we evaluate the electronic width of this new state and argue that its nature is sensitive to its total width, the experimental measurement currently available being unable to distinguish between different options. Our estimates demonstrate that the planned Super $τ$ -Charm Facility offers a promising opportunity to search for and study this new state in the invariant mass distributions for the final states $J / ψ γ$ and $ψ (2 S) γ$ .
↳ hep-phhep-exnucl-thChin.Phys.Lett.(2024)·14 citations
08
Energy and system size dependence of strongly intensive fluctuation measures in heavy-ion collisions at FAIR energies
Bushra Ali🇮🇳 · Shakeel Ahmad🇮🇳 · A. Ahmad🇮🇳
Event-by-event fluctuations of multiplicity and transverse momentum of charged hadrons produced in heavy-ion collisions at FAIR energies, 10A, 20A, 30A and 40A GeV are studied in the framework of relativistic transport model, URQMD. Dependence of two families of strongly intensive measures of multiplicity( $N$ ) and transverse momentum( $p_{T}$ ) fluctuations, $Δ [p_{T}, N]$ and $Σ [p_{T}, N]$ , on collision centrality, centrality bin-widths and pseudorapidity windows are examined. Attempts are also made to study $N N$ , $N$ $p_{T}$ and $p_{T}$ $p_{T}$ fluctuations using two window analysis method. The findings suggest that the measure, $Δ [p_{T}, N]$ be dealt with proper selection of centrality intervals. This measure also exhibits a strong dependence on the widths of $η$ windows. The variable $Σ [p_{T}, N]$ , however, is observed to be insensitive to the centrality bin-widths and shows a variation of $< 5%$ with the widths of $η$ windows. The analysis of data after event mixing gives $Δ [p_{T}, N]$ and $Σ [p_{T}, N]$ values as $\sim 1$ irrespective of the widths of $η$ windows and collision centrality, as predicted by model of independent particle emission, IPM. The study of joint fluctuations of the two quantities on two $η$ windows separated in $η$ space, reveals that $Σ [N_{F}, N_{B}]$ values are $\sim 1$ irrespective of the position of $η$ windows whereas, the values of $Σ [N_{F}, p_{T_{B}}]$ and $Σ [p_{T_{F}}, p_{T_{B}}]$ firstly increase with $η_{se p}$ and later acquire saturations. The observed trend of centrality dependence of $Σ [N_{F}, N_{B}], Σ [N_{F}, p_{T_{B}}]$ and $Σ [p_{T_{F}}, p_{T_{B}}]$ agrees fairly well with those observed in MC simulated studies carried out for AA collisions at LHC energies in the framework model of string fusion.
↳ hep-phnucl-thJ.Phys.G(2024)·1 citation
09
Torsional oscillations of magnetized neutron stars: Impacts of Landau-Rabi quantization of electron motion
Ling Cheung · Lap-Ming Lin · Nicolas Chamel
Torsional oscillations of magnetized neutron stars have been well studied since they may be relevant to the physical interpretation of some of the observed quasiperiodic oscillations in the magnetar giant flares. In the crustal region of a magnetar, the strong magnetic field can alter the equation of state and composition due to the Landau-Rabi quantization of electron motion. In this paper, we study this effect on the crust-confined, torsional oscillation modes of neutron stars with mixed poloidal-toroidal magnetic fields in general relativity under the Cowling approximation. Furthermore, the inner and outer crusts are treated consistently based on the nuclear-energy density functional theory. Depending on the magnetic-field configurations, we find that the Landau-Rabi quantization of electrons can change the frequencies of the fundamental torsional oscillation mode of $1.4 M_{⊙}$ neutron star models with a normal fluid core by about 10% when the magnetic field strength at the pole reaches the order of $1 0^{16}$ G. The shift can even approach 20% at a field strength of $1 0^{15}$ G for neutron stars with a simple model of superconducting core where the magnetic field is assumed to be expelled completely.
↳ astro-ph.HEgr-qcnucl-thPRD(2024)·1 citation
10
Predicting Quadrupole deformation via anisotropic flow and transverse momentum spectra in isotopic $\prescript 128 - 135 54 Xe$ collisions at LHC
Saraswati Pandey🇮🇳 · B. K. Singh🇮🇳
In the hydrodynamical description of heavy-ion collisions, the elliptic flow $v_{2}$ and triangular flow $v_{3}$ are sensitive to the quadrupole deformation $β_{2}$ of the colliding nuclei. We produce $v_{2}$ and $v_{3}$ ratios qualitatively and quantitatively in most-central Xe-Xe collisions at 5.44 TeV. By employing HYDJET++ model, we study the sensitivity of anisotropic flow coefficients and mean transverse momentum to the quadrupole deformation and system-size in isotopic Xe-Xe collisions. Flow observables strongly depend on the strength of nucleon-nucleon scattering occuring in even-A and odd-A nuclei. Flow for odd-A nuclei is suppressed in comparison to flow in even-A collisions. There exists a linear inter-dependence between $p_{T}$ integrated anisotropic flow and nuclear deformation. Mean transverse momentum signifies the fireball temperature in body-body and tip-tip collisions. There exists a negative linear correlation of $⟨ p_{T} ⟩$ with collision system-size and a positive correlation with nuclear deformation. Flow measurements in high-energy, heavy-ion collisions using isotopic collision systems, offer a new precision tool to study nuclear structure physics. Observation of nuclear structure properties like nuclear deformation in a heavy-ion collision such as this would be very interesting.
↳ hep-phnucl-thEPJC(2024)·0 citations
11
Critical dynamics within the real-time fRG approach
Yong-rui Chen🇨🇳 · Yang-yang Tan🇨🇳 · Wei-jie Fu🇨🇳
The Schwinger-Keldysh functional renormalization group (fRG) developed in [1] is employed to investigate critical dynamics related to a second-order phase transition. The effective action of model A is expanded to the order of $O (\partial^{2})$ in the derivative expansion for the $O (N)$ symmetry. By solving the fixed-point equations of effective potential and wave function, we obtain static and dynamic critical exponents for different values of the spatial dimension $d$ and the field component number $N$ . It is found that one has $z \geq 2$ in the whole range of $2 \leq d \leq 4$ for the case of $N = 1$ , while in the case of $N = 4$ the dynamic critical exponent turns to $z < 2$ when the dimension approach towards $d = 2$ .
↳ hep-phnucl-thPRD(2024)·9 citations
12
An Effective Field Theory study of medium heavy quark evolution
Miguel Ángel Escobedo🇪🇸
The evolution of hard probes in a medium is a complex multiscale problem that significantly benefits from the use of Effective Field Theories (EFTs). Within the EFT framework, we aim to define a series of EFTs in a way that addresses each energy scale individually in separate steps. However, studying hard probes in a medium presents challenges. This is because an EFT is typically constructed by formulating the most general Lagrangian compatible with the problem's symmetries. Nevertheless, medium effects may not always be encoded adequately in an effective action. In this paper, we construct an EFT that is valid for studying the evolution of a heavy quark in a QCD plasma containing few other heavy quarks, where degrees of freedom with an energy of the order of the temperature scale are integrated out. Through this example, we explicitly demonstrate how to handle the doubling of degrees that arise in non-equilibrium field theory. As a result, we derive a Fokker-Planck equation using only symmetry and power counting arguments. The methods introduced in this paper will pave the way for future developments in the study of quarkonium suppression.
↳ hep-phnucl-thUniverse(2024)·0 citations
13
Rotating gluon system and confinement
Yin Jiang🇨🇳
In this work the non-abelian gauge theory is reformulated in a local inertial frame with the presence of a background rotation. With this new formalism the influence of the background rotation on the color deconfinement transition for a SU(2) pure gluon system. The KvBLL caloron, which is a color neutral and asymptotically nontrivial solution of Yang-Mills equation at finite temperature, is adopted to confine the color charges. With new solutions of the caloron's constituent particles, i.e. dyons, the semi-classical potential, which confines color charges, and the perturbative potential, induced by the Gaussian fluctuation, have been obtained for this system under rotation. By solving the critical temperature of confinement-deconfinement phase transition in different computation schemes, it is found that neither the rotational semi-classical potential nor Gaussian fluctuations can confine color charges more tightly when the rotation becomes faster. While only a stronger coupling constant is able to make the critical temperature increasing with angular velocity, as that indicated in lattice simulations. And it is also found with some particular sets of parameters, a non-monotonic dependence of the critical temperature will be obtained in the most physically realistic case, in which all the three factors are taken into account.
↳ hep-thhep-phnucl-thPLB(2024)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE