A5022472380- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Synthesis and Characterization of Heterocyclic Compounds
- Synthesis and biological activity
- Synthesis and Biological Evaluation
- Synthesis and Reactions of Organic Compounds
- Structural and Chemical Analysis of Organic and Inorganic Compounds
- Astrophysical Phenomena and Observations
- Synthesis of heterocyclic compounds
- Chemical Synthesis and Reactions
- Geophysics and Gravity Measurements
- Organic Chemistry Cycloaddition Reactions
- Synthesis and Reactivity of Heterocycles
- Solar and Space Plasma Dynamics
- Synthesis and Reactivity of Sulfur-Containing Compounds
- Chemical Reactions and Mechanisms
- Synthesis of Organic Compounds
- Carbon dioxide utilization in catalysis
- Inorganic and Organometallic Chemistry
- Chemical Reaction Mechanisms
- Synthesis and Characterization of Pyrroles
- Microwave-Assisted Synthesis and Applications
- Advanced DC-DC Converters
- Fluorine in Organic Chemistry
Kyoto University
2003-2024
Yokosuka Kyosai Hospital
2023-2024
Instituto de Física Teórica
2024
Yukawa Institute for Theoretical Physics
2024
Kinjo Gakuin University
2024
Rikkyo University
2018-2022
Kobe University
2015-2020
The University of Tokyo
2015-2017
Hyogo University of Health Sciences
2015
Tohoku Bunka Gakuen University
2015
Transradial coronary intervention (TRI) introduces a trauma to the radial artery (RA), possibly influencing quality as bypass conduit if subsequently used. We sought determine acute and chronic effects of TRI on RA by optical coherence tomography (OCT).Immediately after completion, 73 RAs in 69 patients were examined. The sheath was pulled back 2 cm distal puncture site, OCT imaging performed. injuries intimal thickening compared between first-TRI repeat-TRI RAs. Intimal tears observed 49...
The widely accepted threshold of <65 μm for coronary plaque fibrous cap thickness was derived from postmortem studies ruptured plaques and may not be appropriate in vivo rupture-prone plaques. We investigated the relationship between rupture using optical coherence tomography (OCT).We studied 266 lesions (103 patients with acute syndrome 163 stable angina) before percutaneous intervention OCT. Ruptured non-ruptured lipid-rich were identified thinnest most representative determined. Cap...
We propose a novel class of degenerate higher-order scalar-tensor theories as an extension mimetic gravity. By performing noninvertible conformal transformation on "seed" which may be nondegenerate, we can generate large with at most three physical degrees freedom. identify general seed theory for this is possible. Cosmological perturbations in these extended are also studied. It shown that either tensor or scalar plagued gradient instabilities, except special case where the presumably...
Among single-field scalar-tensor theories, there is a special class called "cuscuton", which represented as some limiting case of k-essence in general relativity. This theory has remarkable feature that the number propagating degrees freedom only two unitary gauge contrast to ordinary theories with three freedom. We specify same property cuscuton context beyond Horndeski theory, we dub extended cuscuton. also study cosmological perturbations presence matter these theories.
Abstract Since the discovery of accelerated expansion present universe, significant theoretical developments have been made in area modified gravity. In meantime, cosmological observations providing more high-quality data, allowing us to explore gravity on scales. To bridge recent and observations, we an overview a variety theories observables cosmic microwave background large-scale structure, supplemented with summary predictions for derived from perturbations sophisticated numerical...
Abstract Typically, constraints on parameters of the effective field theory (EFT) dark energy have been obtained in Jordan frame, where matter fields are minimally coupled to gravity. To connect these with those EFT black hole perturbations a timelike scalar profile, it is necessary perform frame transformation general. In this paper, we study conformal/disformal an arbitrary background. Furthermore, explore effect operator M 6 ( r ) σ̅ μ ν δK α , which elusive LIGO/Virgo bound...
We study static spherically symmetric black hole solutions with a linearly time-dependent scalar field and discuss their linear stability in the shift- reflection-symmetric subclass of quadratic degenerate higher-order scalar-tensor (DHOST) theories. present explicit forms reduced system background equations for generic theory within this subclass. Using motion, we show that several cases solution is forced to be Schwarzschild or Schwarzschild--(anti-)de Sitter form. consider odd-parity...
Regardless of the long history gauge theories, it is not well recognized under which condition fixing at action level legitimate. We address this issue from Lagrangian point view, and prove following theorem on relation between Euler-Lagrange equations: In any theory, if a complete, i.e., functions are determined uniquely by conditions, equations derived gauge-fixed equivalent to those original supplemented with conditions. Otherwise, appropriate impose conditions before deriving as may in...
We explore General Relativity solutions with stealth scalar hair in general quadratic higher-order scalar-tensor theories.Adopting the assumption that field has a constant kinetic term, we derive fully covariant manner set of conditions under which Euler-Lagrange equations allow as exact presence matter component minimally coupled to gravity.The possesses nontrivial profile, can be obtained by integrating condition term for each metric solution.We demonstrate construction profile several...
We consider a higher-derivative generalization of disformal transformations in $D$-dimensional spacetime and clarify the conditions under which they form group with respect to matrix product functional composition. These allow us systematically construct inverse transformation fully covariant manner. Applying invertible generalized known ghost-free scalar-tensor theories, we obtain novel class whose action contains third- or higher-order derivatives scalar field as well nontrivial derivative...
Modified gravity theories can accommodate exact solutions, for which the metric has same form as one in general relativity, i.e., stealth solutions. One problem with these solutions is that perturbations around them exhibit strong coupling when are realized degenerate higher-order scalar-tensor theories. We show be circumvented framework of so-called U-DHOST theories, degeneracy partially broken such a way higher-derivative terms only unitary gauge. In this sense, scordatura effect built-in...
Invertible disformal transformations are a useful tool to investigate ghost-free scalar-tensor theories. By performing higher-derivative generalization of the invertible transformation on Horndeski theories, we construct novel class which dub generalized Specifically, these theories lie beyond quadratic/cubic DHOST class. We explore cosmological perturbations identify subclass where gravitational waves propagate at speed light and clarify conditions for absence ghost/gradient instabilities...
The Effective Field Theory (EFT) of perturbations on an arbitrary background geometry with a timelike scalar profile was recently constructed in the context scalar-tensor theories. In this paper, we use EFT to study quasinormal frequencies odd-parity static and spherically symmetric black hole background. Keeping set operators that can accommodate shift-symmetric quadratic higher-order theories, demonstrate computation for two examples hairy holes, which one is stealth Schwarzschild solution...
Abstract We study static tidal Love numbers (TLNs) of a and spherically symmetric black hole for odd-parity metric perturbations. describe perturbations using the effective field theory (EFT), formulated on an arbitrary background with timelike scalar profile in context scalar-tensor theories. In particular, we obtain solution generalized Regge-Wheeler equation order by modified-gravity parameter extract TLNs uniquely analytic continuation multipole index ℓ to non-integer values. For stealth...
Abstract We formulate the effective field theory (EFT) of vector-tensor gravity for perturbations around an arbitrary background with a timelike vector profile, which can be applied to study black hole perturbations. The profile spontaneously breaks both time diffeomorphism and U(1) symmetry, leaving their combination spatial as residual symmetries in unitary gauge. derive two sets consistency relations guarantee EFT. Also, we provide dictionary between our EFT coefficients those generalized...
Abstract It has recently been pointed out that one can construct invertible conformal transformations with a parity-violating factor, which be employed to generate novel class of ghost-free metric theories from general relativity. We obtain exact solutions for rotating black holes in such by performing the transformation on Kerr solution relativity, we dub solutions. explore geodesic motion test particle spacetime. While null geodesics remain same as those spacetime, timelike exhibit...
An invertible field transformation is such that the old variables correspond one-to-one to new variables. As such, one may think two systems are related by an physically equivalent. However, if depends on derivatives, equivalence between nontrivial due appearance of higher derivative terms in equations motion. To address this problem, we prove following theorem relation and Euler-Lagrange equations: If invertible, then any solution original set mapped a equations, vice versa. We also present...
Abstract We study U-DHOST theories, i.e., higher-order scalar-tensor theories which are degenerate only in the unitary gauge and yield an apparently unstable extra mode a generic coordinate system. show that satisfies three-dimensional elliptic differential equation on spacelike hypersurface, hence it does not propagate. clarify how to treat this “shadowy” at both linear nonlinear levels.
We study linear perturbations about static and spherically symmetric black holes with a time-independent background scalar field in shift-symmetric Horndeski theories, whose Lagrangian is characterized by coupling functions depending only on the kinetic term of $X$. clarify conditions for absence ghosts Laplacian instabilities along radial angular directions both odd- even-parity perturbations. For reflection-symmetric theories described k-essence nonminimal derivative Ricci scalar, we show...
In full Horndeski theories, we show that the static and spherically symmetric black hole (BH) solutions with a scalar field $\ensuremath{\phi}$ whose kinetic term $X$ is nonvanishing on BH horizon are generically prone to ghost/Laplacian instabilities. We then search for asymptotically Minkowski hairy vanishing free from models regular coupling functions of result in no-hair Schwarzschild BHs general. On other hand, presence between Gauss-Bonnet (GB) ${R}_{\mathrm{GB}}^{2}$, even coexistence...
Abstract Recently, the Effective Field Theory (EFT) of perturbations on an arbitrary background metric with a timelike scalar profile was formulated in context scalar-tensor theories. Here, we generalize dictionary between coefficients EFT action and those covariant theories to accommodate shift- reflection-symmetric quadratic higher-order theories, including DHOST as well U-DHOST. We then use study dynamics odd-parity static spherically symmetric black hole profile. Finally, obtain...
Invertible disformal transformations serve as a useful tool to explore ghost-free scalar-tensor theories. In this paper, we construct generalization of invertible that involves arbitrary higher-order covariant derivatives the scalar field. As result, obtain more general class theories than ever. Notably, our is such matter fields can be consistently coupled these without introducing an unwanted extra degree freedom in unitary gauge.
Abstract Generalized disformal transformations enable us to construct the generalized Horndeski theories, which form most general class of ghost-free scalar-tensor theories this date. We extend effective field theory (EFT) cosmological perturbations incorporate these theories. The main difference from conventional EFT is that our extended involves operators with higher spatial derivatives lapse function. Our also accommodates transformation U-DHOST
Recently, a generalization of invertible disformal transformations containing higher-order derivatives scalar field has been proposed in the context scalar-tensor theories gravity. By applying this generalized transformation to Horndeski theory, one can obtain so-called (GDH) which are more general healthy than ever. However, it is unclear whether or not GDH be coupled consistently matter fields because introducing could break degeneracy conditions and hence yield unwanted Ostrogradsky...