146 citations · 299 across the 17 of their papers we have counts for
17 papers
On the (Non)Unitarity with respect to the Clock of a Dynamical Local Observer and the Einstein Equivalence Principle
Kengo Shimada
We investigate the unitarity of quantum evolution relative to an internal time defined by a local observer's clock. The observer is modeled as a relativistic particle carrying both…
Insights on the Scale of Leptogenesis from Neutrino Masses and Neutrinoless Double-Beta Decay
Alessandro Granelli, Koichi Hamaguchi, Maura E. Ramirez-Quezada +3
We revisit the thermal leptogenesis scenario in the type-I seesaw framework featuring three heavy Majorana neutrinos with a hierarchical mass spectrum. We focus on low energy obser…
Derivation of the GKP-Witten relation by symmetry without Lagrangian
Sinya Aoki, Janos Balog, Kengo Shimada
We derive the GKP-Witten relation in terms of correlation functions by symmetry without referring to a Lagrangian or the large expansion. By constructing bulk operators from bo…
AdS/CFT correspondence for the invariant critical model in 3-dimensions by the conformal smearing
Sinya Aoki, Kiyoharu Kawana, Kengo Shimada
We investigate a structure of a 4-dimensional bulk space constructed from the invariant critical model in 3-dimension using the conformal smearing. We calculate a bulk…
Geometric conservation in curved spacetime and entropy
Sinya Aoki, Yoshimasa Hidaka, Kiyoharu Kawana +1
We provide an improved definition of new conserved quantities derived from the energy-momentum tensor in curved spacetime by introducing an additional scalar function. We find that…
Bulk modified gravity from a thermal CFT by the conformal flow
Sinya Aoki, János Balog, Kiyoharu Kawana +1
We construct a bulk spacetime from a boundary CFT, free scalar model, at finite temperature using a smearing technique, called a conformal flow. The bulk metric is construct…
Entanglement Generation and Decoherence in a Two-Qubit System Mediated by Relativistic Quantum Field
Yoshimasa Hidaka, Satoshi Iso, Kengo Shimada
Motivated by the Bose et al.-Matletto-Vedral (BMV) proposal for detecting quantum superposition of spacetime geometries, we study a toy model of a quantum entanglement generation b…
Complementarity and causal propagation of decoherence by measurement in relativistic quantum field theories
Yoshimasa Hidaka, Satoshi Iso, Kengo Shimada
Entanglement generation by Newtonian gravitational potential between objects has been widely discussed to reveal the quantum nature of gravity. In this paper, we perform a quantum…
Axion-CMB Scenario in Supercooled Universe
Satoshi Iso, Kiyoharu Kawana, Kengo Shimada
Axion-CMB scenario is an interesting possibility to explain the temperature anisotropy of the cosmic microwave background (CMB) by primordial fluctuations of the QCD axion \cite{Is…
QCD Axions and CMB Anisotropy
Satoshi Iso, Kiyoharu Kawana, Kengo Shimada
In this paper, we consider a possibility that the temperature anisotropy of cosmic microwave background (CMB) is dominantly generated by the primordial fluctuations of QCD-axion li…
Asymptotic Scale Invariance and its Consequences
Mikhail Shaposhnikov, Kengo Shimada
Scale invariance supplemented by the requirement of the absence of new heavy particles may play an important role in addressing the hierarchy problem. We discuss how the Standard M…
QCD-Electroweak First-Order Phase Transition in a Supercooled Universe
Satoshi Iso, Pasquale D. Serpico, Kengo Shimada
If the electroweak sector of the standard model is described by classically conformal dynamics, the early Universe evolution can be substantially altered. It is already known that-…
Dynamical fine-tuning of initial conditions for small field inflations
Satoshi Iso, Kazunori Kohri, Kengo Shimada
Small-field inflation (SFI) is widely considered to be unnatural because an extreme fine-tuning of the initial condition is necessary for sufficiently large e-folding. In this pape…
Small Field Coleman-Weinberg Inflation driven by Fermion Condensate
Satoshi Iso, Kazunori Kohri, Kengo Shimada
We revisit the small field Coleman-Weinberg (CW) inflation, which has the following two problems. First, the smallness of the slow roll parameter requires the inflation scale t…
Coherent Flavour Oscillation and CP Violating Parameter in Thermal Resonant Leptogenesis
Satoshi Iso, Kengo Shimada
Solving the Kadanoff-Baym (KB) equations in a different method from our previous analysis, we obtain the CP violating parameter in the thermal resonant leptogenesis w…
Kadanoff-Baym approach to the thermal resonant leptogenesis
Satoshi Iso, Kengo Shimada, Masato Yamanaka
Using the non-equilibrium Green function method (Kadanoff-Baym equations) in the expanding universe, we investigate evolution of the lepton number asymmetry when the right-handed (…
The Einstein equation of state as the Clausius relation with an entropy production
Kengo Shimada, Susumu Okazawa, Satoshi Iso
We give a modified derivation of the Einstein equation of state by considering the Clausius relation on a null hypersurface with a non-vanishing expansion (),…