In this paper, we study non-equilibrium dynamics induced by a sudden quench of strongly correlated Hamiltonians with all-to-all interactions. By relying on a Sachdev-Ye-Kitaev (SYK)-based quench ...protocol, we show that the time evolution of simple spin-spin correlation functions is highly sensitive to the degree of k-locality of the corresponding operators, once an appropriate set of fundamental fields is identified. By tracking the time-evolution of specific spin-spin correlation functions and their decay, we argue that it is possible to distinguish between operator-hopping and operator growth dynamics; the latter being a hallmark of quantum chaos in many-body quantum systems. Such an observation, in turn, could constitute a promising tool to probe the emergence of chaotic behavior, rather accessible in state-of-the-art quench setups.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
D-type fiber-base duality Haghighat, Babak; Kim, Joonho; Yan, Wenbin ...
The journal of high energy physics,
09/2018, Volume:
2018, Issue:
9
Journal Article
Peer reviewed
Open access
A
bstract
M5 branes probing D-type singularities give rise to 6d (1,0) SCFTs with SO × SO flavor symmetry known as D-type conformal matter theories. Gauging the diagonal SO-flavor symmetry leads to a ...little string theory with an intrinsic scale which can be engineered in F-theory by compactifying on a doubly-elliptic Calabi-Yau manifold. We derive Seiberg-Witten curves for these little string theories which can be interpreted as mirror curves for the corresponding Calabi-Yau manifolds. Under fiber-base duality these models are mapped to D-type quiver gauge theories and we check that their Seiberg-Witten curves match. By taking decompactification limits, we construct the curves for the related 6d SCFTs and connect to known results in the literature by further taking 5d and 4d limits.
Faint z ∼ 5 quasars with M1450 ∼ −23 mag are known to be potentially important contributors to the ultraviolet ionizing background in the postreionization era. However, their number density has not ...been well determined, making it difficult to assess their role in the early ionization of the intergalactic medium (IGM). In this work, we present the updated results of our z ∼ 5 quasar survey using the Infrared Medium-deep Survey (IMS), a near-infrared imaging survey covering an area of 85 deg2. From our spectroscopic observations with the Gemini Multi-Object Spectrograph on the Gemini-South 8 m telescope, we discovered eight new quasars at z ∼ 5 with −26.1 ≤ M1450 ≤ −23.3. Combining our IMS faint quasars (M1450 > −27 mag) with the brighter Sloan Digital Sky Survey quasars (M1450 < −27 mag), we derive the z ∼ 5 quasar luminosity function (QLF) without any fixed parameters down to the magnitude limit of M1450 = −23 mag. We find that the faint-end slope of the QLF is very flat ( ), with a characteristic luminosity of mag. The number density of z ∼ 5 quasars from the QLF gives an ionizing emissivity at 912 of 912 = (3.7-7.1) × 1023 erg s−1 Hz−1 Mpc−3 and an ionizing photon density of Mpc−3 s−1. These results imply that quasars are responsible for only 10%-20% (up to 50% even in the extreme case) of the photons required to completely ionize the IGM at z ∼ 5, disfavoring the idea that quasars alone could have ionized the IGM at z ∼ 5.
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•A hierarchical OER electrocatalyst with high activity and stability was fabricated.•Hydroxide was formed on the electrode surface synthesized by electrodeposition.•Surface morphology ...and structure relative to plating bath concentration were analyzed.•OER performance was examined with respect to the Ni:Fe ratio of the plating bath.•The optimized electrocatalysts demonstrated high OER performances in alkaline media.
This study fabricated an OER electrocatalyst with a hierarchical structure by electrodepositing Ni-Fe on NiO. The prepared electrocatalyst exhibited high activity and stability. Furthermore, the OER characteristics of the NiFe/NiO electrode were investigated by changing the metal (Ni and Fe) concentration and Ni:Fe ratio in the plating bath. As the plating bath concentration decreased, NiFe-layered double hydroxide was prominently formed due to an increase in local pH. The electrode obtained using a relatively low plating bath concentration of 130 mM demonstrated high activity with an overpotential of 245 mV and Tafel slope of 27.6 mV dec-1 at a current density of 10 mA/cm2. When the Ni:Fe ratio in the plating bath was adjusted, OER activity increased as the Fe content of the electrode increased to approximately 20.9 at.%, and as the Fe content increased beyond that, the activity gradually decreased. Fe inhibits Ni oxidation and acts as an active site owing to Fe3+ substitution in the γ-NiOOH structure, resulting in increased OER activity. However, when the Fe content was > 29 at.%, the inactive phase γ-FeOOH predominantly grew and the OER activity decreased.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The prognosis of patients with embolic stroke of undetermined source (ESUS) may vary according to the underlying cause. Therefore, we aimed to divide ESUS into subtypes and assess the long-term ...outcomes. Consecutive patients with acute ischemic stroke who underwent a comprehensive workup, including transesophageal echocardiography and prolonged electrocardiography monitoring, were enrolled. We classified ESUS into minor cardioembolic (CE) ESUS, arteriogenic ESUS, two or more causes ESUS, and no cause ESUS. Arteriogenic ESUS was sub-classified into complex aortic plaque (CAP) ESUS and non-stenotic (< 50%) relevant artery plaque (NAP) ESUS. A total of 775 patients were enrolled. During 1286 ± 748 days follow-up, 116 major adverse cardiovascular events (MACE) occurred (4.2 events/100 patient-years). Among the ESUS subtypes, CAP ESUS was associated with the highest MACE frequency (9.7/100 patient-years, p = 0.021). Cox regression analyses showed that CAP ESUS was associated with MACE (hazard ratio 2.466, 95% confidence interval 1.305-4.660) and any stroke recurrence (hazard ratio 2.470, 95% confidence interval, 1.108-5.508). The prognosis of ESUS varies according to the subtype, with CAP ESUS having the worst prognosis. Categorizing ESUS into subtypes could improve patient care and refine clinical trials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
One of the keys to the success of multimessenger astronomy is the rapid identification of the electromagnetic wave counterpart, kilonova (KN), of the gravitational-wave (GW) event. Despite ...its importance, it is hard to find a KN associated with a GW event, due to a poorly constrained GW localization map and numerous signals that could be confused as a KN. Here, we present the Gravitational-wave Electromagnetic wave Counterpart Korean Observatory (GECKO) project, the GECKO observation of GW190425, and prospects of GECKO in the fourth observing run (O4) of the GW detectors. We outline our follow-up observation strategies during O3. In particular, we describe our galaxy-targeted observation criteria that prioritize based on galaxy properties. Armed with this strategy, we performed an optical and/or near-infrared follow-up observation of GW190425, the first binary neutron star merger event during the O3 run. Despite a vast localization area of 7460 deg
2
, we observed 621 host galaxy candidates, corresponding to 29.5% of the scores we assigned, with most of them observed within the first 3 days of the GW event. Ten transients were discovered during this search, including a new transient with a host galaxy. No plausible KN was found, but we were still able to constrain the properties of potential KNe using upper limits. The GECKO observation demonstrates that GECKO can possibly uncover a GW170817-like KN at a distance <200 Mpc if the localization area is of the order of hundreds of square degrees, providing a bright prospect for the identification of GW electromagnetic wave counterparts during the O4 run.
Erratum to: Instantons from blow-up Kim, Joonho; Kim, Sung-Soo; Lee, Ki-Hong ...
The journal of high energy physics,
06/2020, Volume:
2020, Issue:
6
Journal Article
Peer reviewed
Open access
Corrected the authors’ affiliations. Affiliation a and c were swapped.
A 4d N = 1 Cardy Formula Kim, Joonho; Kim, Seok; Song, Jaewon
The journal of high energy physics,
01/2021, Volume:
2021, Issue:
1
Journal Article
Peer reviewed
Open access
A
bstract
We study the asymptotic behavior of the (modified) superconformal index for 4d
N
= 1 gauge theory. By considering complexified chemical potential, we find that the ‘high-temperature limit’ ...of the index can be written in terms of the conformal anomalies 3
c −
2
a
. We also find macroscopic entropy from our asymptotic free energy when the Hofman-Maldacena bound 1/2 <
a
/
c
< 3/2 for the interacting SCFT is satisfied. We study
N
= 1 theories that are dual to AdS
5
×
Y
p,p
and find that the Cardy limit of our index accounts for the Bekenstein-Hawking entropy of large black holes.
Background: Although decades have passed since the introduction of pharmacologically induced hypertensive therapy (PIHT) against early neurologic deterioration (END) in acute ischemic stroke, the ...optimal duration of PIHT remains elusive. Case Report: A 70-year-old man developed right hemiplegia and aphasia 25 hours before arrival. Computed tomography angiography (CTA) revealed acute infarction in the left middle cerebral artery (MCA) territory and occlusion of the left internal carotid artery. He experienced END 36 hours after admission, and CTA revealed a newly developed proximal MCA occlusion. PIHT was initiated to augment cerebral perfusion. As his neurologic symptoms were highly dependent on blood pressure, PIHT was inevitably sustained for over 3 weeks. Follow-up CTA revealed recanalization of the MCA.Conclusion: Although further investigation is required to expedite the future clinical application, prolonged PIHT may serve as a viable collateral-enhancing treatment for a certain subset of patients with END without alternative treatment options.
γ-GeSe is a newly identified polymorph among group-IV monochalcogenides, characterized by a distinctive interatomic bonding configuration. Despite its promising applications in electrical and thermal ...domains, the experimental verification of its mechanical and thermal properties remains unreported. Here, we experimentally characterize the in-plane Young’s modulus (
E
) and thermal conductivity (
) of γ-GeSe. The mechanical vibrational modes of freestanding γ-GeSe flakes are measured using optical interferometry. Nano-indentation via atomic force microscopy is also conducted to induce mechanical deformation and to extract the
E
. Comparison with finite-element simulations reveals that the
E
is 97.3
7.5 GPa as determined by optical interferometry and 109.4
13.5 GPa as established through the nano-indentation method. Additionally, optothermal Raman spectroscopy reveals that γ-GeSe has a lattice thermal conductivity of 2.3
0.4 Wm
−1
K
−1
and a total thermal conductivity of 7.5
0.4 Wm
−1
K
−1
in the in-plane direction at room temperature. The notably high
ratio in γ-GeSe, compared to other layered materials, underscores its distinctive structural and dynamic characteristics.
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