Entanglement Entropy for 2D Gauge Theories with Matters

We investigate the entanglement entropy in 1+1-dimensional $SU(N)$ gauge theories with various matter fields using the lattice regularization. Here we use extended Hilbert space definition for entanglement entropy, which contains three contributions; (1) classical Shannon entropy associated with superselection sector distribution, where sectors are labelled by irreducible representations of boundary penetrating fluxes, (2) logarithm of the dimensions of their representations, which is associated with "color entanglement", and (3) EPR Bell pairs, which give "genuine" entanglement. We explicitly show that entanglement entropies (1) and (2) above indeed appear for various multiple "meson" states in gauge theories with matter fields. Furthermore, we employ transfer matrix formalism for gauge theory with fundamental matter field and analyze its ground state using hopping parameter expansion (HPE), where the hopping parameter $K$ is roughly the inverse square of the mass for the matter. We evaluate the entanglement entropy for the ground state and show that all (1), (2), (3) above appear in the HPE, though the Bell pair part (3) appears in higher order than (1) and (2) do. With these results, we discuss how the ground state entanglement entropy in the continuum limit can be understood from the lattice ground state obtained in the HPE.Comment: 73 pages, 7 figure

Study on Lambda(1405) in the flavor SU(3) limit in the HAL QCD method

We study interactions between the S-wave octet pseudo-scalar (PS) meson and octet baryon in the flavor SU(3) limit using the HAL QCD method at the PS meson mass $m_M\approx 670~\textrm{MeV}$. We focus on the singlet and two octet channels, where the poles corresponding to $\Lambda(1405)$ have been predicted in the chiral unitary model. For calculations with $\Lambda$-baryon source operators with zero momentum, we employ the conventional stochastic calculation combined with the covariant-approximation averaging to calculate the all-to-all propagators. Due to a zero of the R-correlator (a kind of wave function), the leading order (LO) potential obtained by the single channel analysis has a singular point in all channels, which makes it difficult to obtain reliable binding energies. To overcome this problem, we take a linear combination of two octet R-correlators with a relative weight such that it does not cross zero, as two octet channels are suggested to couple to the same low-energy states with different weights. The potential calculated from such the linear combination shows strong attraction without singularities, though its shape depends on the relative weight. Our estimation for the binding energy in the octet channel is $E^{8_{s(a)}}_{\textrm{bind}}=163(7)(^{+16} _{-64})~\textrm{MeV}$, which is consistent with 156(8) MeV estimated from the two-point correlation function within errors.Comment: 7 pages, 2 figures, 2 tables, Proceedings of the 40th International Symposium on Lattice Field Theory (Lattice 2023) at Fermilab, Batavia, Illinois, USA, from July 31 to August 4, 202

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

We study decuplet baryons from meson–baryon interactions in lattice quantum chromodynamics (QCD), in particular, Δ and Ω baryons from P-wave I = 3/2 Nπ and I = 0 $Xi bar{K}$ interactions, respectively. Interaction potentials are calculated in the HAL QCD method using 3-quark-type source operators at mπ ≈ 410 MeV and mK ≈ 635 MeV, where Δ as well as Ω 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 Nπ system while the binding energy from the threshold is larger for Ω than Δ. This suggests that an inequality $m_{N}+m_{pi }-m_{Delta }lt m_{Xi }+m_{bar{K}}-m_{Omega }$ 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 Δ and Ω are tightly bound states and thus can be regarded qualitatively as composite states of three quarks. Results of binding energies agree with those obtained from temporal two-point functions within large systematic errors, which arise dominantly from the lattice artifact at short distances

First Detection of 12CO (1--0) Emission from Two Narrow-Line Seyfert 1 Galaxies

In order to investigate how the growth of galactic bulges progresses with the growth of central black holes (BHs), we observed molecular gas (fuel for the coming star formation) in possibly young active galaxies, narrow-line Seyfert 1 galaxies (NLS1s). We present the results of radio observations of 12CO(1--0) using the Nobeyama Millimeter Array (with 2--4 kpc spatial resolution) for two FIR-bright NLS1s, yielding the first detection of their CO emission. Corresponding molecular--gas masses M(H2) of (1-3) X 109 Msun are the 2nd and 4th largest ones among NLS1s. By estimating dynamical masses and bulge masses M(bulge) for these two NLS1s using CO channel map and CO line widths, we found M(H2) amount to 0.13--0.35 of these masses. Taking account the star formation efficiency (~ 0.1), the increase in M(bulge) in those NLS1s in the near future (~< 10^{7.5} yr) is expected not to be a huge fraction (1--5% of the preexisting stars). Bulge growth may have finished before BH growth, or bulge--BH coevolution may proceed with many, occasional discrete events, where one coevolution event produces only a small amount of mass growth of BHs and of bulges. We also discuss the ratios of star-formation rate--to--gas accretion rate onto BHs, finding that two NLS1s have very small ratios (~ 1) compared with the M(bulge)/M(BH) ratios found in active and inactive galaxies (~ 700). This huge difference suggests either the non-overlapped coevolution, long star formation duration or temporarily high accretion rate during NLS1 phase.Comment: 29 pages, 8 figures, Accepted for publication in The Astrophysical Journa

Autotaxin has lysophospholipase D activity leading to tumor cell growth and motility by lysophosphatidic acid production

Autotaxin (ATX) is a tumor cell motility–stimulating factor, originally isolated from melanoma cell supernatants. ATX had been proposed to mediate its effects through 5′-nucleotide pyrophosphatase and phosphodiesterase activities. However, the ATX substrate mediating the increase in cellular motility remains to be identified. Here, we demonstrated that lysophospholipase D (lysoPLD) purified from fetal bovine serum, which catalyzes the production of the bioactive phospholipid mediator, lysophosphatidic acid (LPA), from lysophosphatidylcholine (LPC), is identical to ATX. The Km value of ATX for LPC was 25-fold lower than that for the synthetic nucleoside substrate, p-nitrophenyl-tri-monophosphate. LPA mediates multiple biological functions including cytoskeletal reorganization, chemotaxis, and cell growth through activation of specific G protein–coupled receptors. Recombinant ATX, particularly in the presence of LPC, dramatically increased chemotaxis and proliferation of multiple different cell lines. Moreover, we demonstrate that several cancer cell lines release significant amounts of LPC, a substrate for ATX, into the culture medium. The demonstration that ATX and lysoPLD are identical suggests that autocrine or paracrine production of LPA contributes to tumor cell motility, survival, and proliferation. It also provides potential novel targets for therapy of pathophysiological states including cancer

Epidemiological Survey of Severe Fever with Thrombocytopenia Syndrome Virus in Ticks in Nagasaki, Japan

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease endemic in East Asia. Transmitted to other organisms by infected ticks, the SFTS virus (SFTSV) and is endemic to Nagasaki in western Japan. However, epidemiological information regarding SFTSV in Nagasaki ticks has not been available to date. In this study, we began by examining the sensitivities of SFTSV gene detection by real-time RT-PCR and virus isolation in cultured cells and mice. These methods could detect SFTSV in the samples containing more than 4 × 10° ffu. Next, we attempted to isolate SFTSV and to detect viral gene in 2,222 nymph and adult ticks collected from May to August 2013 among seven regions of Nagasaki. However, neither virus isolation nor viral gene detection were confirmed in the tick pools. SFTSV positivity rates are considered to be very low in ticks, and viral loads are also very limited. Further investigations increasing the number of ticks and including larval samples as well as improved detection methods, may be required to find SFTSV-positive ticks in this region