We discuss our recent publication (arXiv:1505.07863 [hep-lat]) of the first lattice QCD calculation of the complex kaon decay amplitude A_0 with physical kinematics, using a single 32^3 x 64 domain wall ensemble with G-parity spatial boundary conditions. We obtain approximate agreement with the experimental value for Re(A_0), which serves as a test of our method. Our prediction of Im(A_0) can be used to compute the direct CP violating ratio Re(ε′/ε), which we find to be ~2 sigma lower than the experimental value. This result provides a new test of the Standard Model theory of CP violation, one which can be made more accurate with increasing computer capability.

Black hole information paradox (BHIP) is an old but unsolved problem. There is an intense controversy regarding a satisfactory resolution of the problem, which, in our point of view may lead to new physics. We consider a novel approach to address this issue.
The idea is based on
adapting, to the situation at hand, the modified versions of quantum theory involving spontaneous stochastic dynamical collapse of quantum states, which have been considered in attempts to deal with shortcomings of the standard Copenhagen interpretation of quantum mechanics, in particular, the issue known as “the measurement problem”. The new basic hypothesis is that this modified (stochastic) quantum behavior is enhanced in the region of high curvature so that the information encoded in the initial quantum state of the matter fields is rapidly erased as the black hole singularity is approached. We show that in this manner the complete evaporation of the black hole via Hawking radiation can be understood as involving no paradox.

REFERENCES:
[1] S. K. Modak, L. Ortíz, I. Peña and D.
Sudarsky, Phys. Rev. D 91,
124009 (2015).
[2] S. K. Modak, L. Ortíz, I. Peña and D.
Sudarsky, Gen. Rel. Grav. 47,
120 (2015).

Quantum Energy teleportation (QET) is a protocol that allows one to teleport energy making use of pre-existing entanglement of the ground state of quantum many-body systems or quantum fields. I will review the latest results on QET and I will explain its implications on information thermodynamics, such as quantum Maxwell demons and Black Hole thermodynamics. I will also comment on current experimental prospects for QET via the quantum Hall effect.

We propose a novel method to probe primordial gravitational waves by means of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations on comoving scales much smaller than those relevant to Cosmic Microwave Background is very large, it induces scalar perturbations due to second-order effects substantially. If the amplitude of resultant scalar perturbations becomes too large, then PBHs are overproduced to a level that is inconsistent with a variety of existing observations constraining their abundance. This leads to upper bounds on the amplitude of initial tensor perturbations on super-horizon scales. The resultant PBH upper bounds turn out be tighter than other bounds obtained from Big Bang Nucleosynthesis and Cosmic Microwave Background.

We have investigated effects of interaction terms on non-perturbative particle production. It is well known that a time-varying background induces abundant particle production, such as the preheating theory. As our conclusion, it is possible to induce particle production even if particles do not couple to the background directly. Such particles are produced through the interactions with other fields, which couple to a time-varying background. Especially, the resonant proccess due to the coherent oscillation of the background induces sizable amount of particles which do not couple to the background directly. In this talk, we will explain with a simple but illustrative model and show analytic and numerical results.

We consider hybrid inflation for small couplings of the inflaton to matter such that the critical value of the inflaton field exceeds the Planck mass. It has recently been shown that inflation then continues at subcritical inflaton field values where quantum fluctuations generate an effective inflaton mass. The effective inflaton potential interpolates between a quadratic potential at small field values and a plateau at large field values. An analysis of the allowed parameter space leads to predictions for the scalar spectral index n_s and the tensor-to-scalar ratio r similar to those of natural inflation. Using the ranges for n_s and r favored by the Planck data, we find that the energy scale of the plateau is constrained to the interval (1.6 − 2.4) × 10^16 GeV, which includes the energy scale of gauge coupling unification in the supersymmetric standard model. The tensor-to-scalar ratio is predicted to satisfy the lower bound r > 0.049 for 60 e-folds before the end of inflation.

Counterfactual communication is a communication without particles in the transmission channel. Since there are no particles to observe, it apparently cryptographically secure because Eve has nothing to eavesdrop on. However, the issue is highly controversial. I will describe: interaction-free measurements, counterfactual key distribution, and direct counterfactual communication protocols. Analyzing the weak trace left in the transmission channel, I will argue that counterfactual communication is possible only for one bit value.

Experimental evidence obtained from photons passing through a nested Mach-Zehnder interferometer shows that they have been in the parts of the interferometer through which they could not have possibly pass. The meaning of these results and numerous objections are discussed. It is argued that the most simple and clear explanation is given in the framework of the two-state vector formalism of quantum theory.

The existence of neutrino oscillations calls for an extension of the Standard Model that would generate neutrino masses and mixing. We focused for these studies on a typical low-scale seesaw mechanism, the inverse seesaw, and its supersymmetric realization. New fermionic gauge singlets around the TeV scale with potentially large couplings lead to a rich phenomenology. After introducing the models considered, I will present their predictions for for lepton flavour violating (LFV) observables in light of the recent CMS excess in the Higgs to tau mu channel and future experimental sensitivities to LFV lepton decays.

We study collider phenomenology in the supersymmetric Standard Model with a certain type of non-universal gaugino masses at the gauge coupling unification scale, motivated by the little hierarchy problem. In this scenario, especially the wino mass is relatively large compared to the gluino mass at the unification scale, and the heavy wino can relax the fine-tuning of the higgsino mass parameter,so-called μ parameter. Besides, it will enhance the lightest Higgs boson mass due to the relatively large left-right mixing of top squarks through the renormalization group (RG) effect. Then 125GeV Higgs boson could be accomplished, even if the top squarks are lighter than 1TeV and the μ parameter is within a few hundreds GeV. The right-handed top squark tends to be lighter than the other sfermions due to the RG runnings, then we focus on the top squark search at the LHC. Since the top squark is almost right-handed and the higgsinos are nearly degenerate, 2b + MET channel is the most sensitive to this scenario. We figure out current and expected experimental bounds on the lightest top squark mass and model parameters at the gauge coupling unification scale.