Wigner-Araki-Yanase theorem on Distinguishability

The presence of an additive conserved quantity imposes a limitation on the measurement process. According to the Wigner-Araki-Yanase theorem, the perfect repeatability and the distinguishability on the apparatus cannot be attained simultaneously. Instead of the repeatability, in this paper, the distinguishability on both systems is examined. We derive a trade-off inequality between the distinguishability of the final states on the system and the one on the apparatus. The inequality shows that the perfect distinguishability of both systems cannot be attained simultaneously.Comment: To be published in Phys.Rev.

Coherent driving and freezing of bosonic matter wave in an optical Lieb lattice

While kinetic energy of a massive particle generally has quadratic dependence on its momentum, a flat, dispersionless energy band is realized in crystals with specific lattice structures. Such macroscopic degeneracy causes the emergence of localized eigenstates and has been a key concept in the context of itinerant ferromagnetism. Here we report the realization of a "Lieb lattice" configuration with an optical lattice, which has a flat energy band as the first excited state. Our optical lattice potential possesses various degrees of freedom about its manipulation, which enables coherent transfer of a Bose-Einstein condensate into the flat band. In addition to measuring lifetime of the flat band population for different tight-binding parameters, we investigate the inter-sublattice dynamics of the system by projecting the sublattice population onto the band population. This measurement clearly shows the formation of the localized state with the specific sublattice decoupled in the flat band, and even detects the presence of flat-band breaking perturbations, resulting in the delocalization. Our results will open up the possibilities of exploring physics of flat band with a highly controllable quantum system.Comment: 13 pages, 9 figures. v2: Title changed, 1 reference correcte

Observation of Chiral-Mode Domains in a Frustrated XY Model on Optical Triangular Lattices

We investigated the relaxation and excitation in a frustrated XY model realized by a Bose gas in Floquet-engineered optical triangular lattices. Periodically driving the position of the entire lattice structure enables the sign inversion of tunneling amplitudes, which, in the case of a triangular lattice, results in geometrical frustration of the local phase of wave packets. We revealed that the two spiral phases with chiral modes show significant differences in relaxation time from the initial ferromagnetic phase. While spontaneous symmetry breaking is clearly observed at a slow ramp of the Floquet drive, simultaneous occupation of two ground states often occurs at a fast ramp, which can be attributed to the domain formation of the chiral modes. The interference of the spatially separated chiral modes was observed, using a quantum gas microscope. This work leads to exploring the domain formation mechanism in a system with U(1)$\times \mathbb{Z}_2$ symmetry.Comment: 5+10 pages, 4+8 figure

Low Frequency Ultrasonic Array Imaging using Signal Post-processing for Concrete Material

The use of ultrasonic arrays for conducting non-destructive evaluation has been drastically increased in recent years. As one of the array imaging, a post-processing beam-forming technique has been proposed that utilizes a complete set of signals of all combinations of transmission and reception elements. This approach is referred to as full matrix capture (FMC) [1]. In FMC, each array element is sequentially used as an emitter and all other array elements are used as receivers. By changing the emitting element, we obtained a set of flaw signals that was used to form the focal beam. The delay-and-sum beam reconstruction based on the post-processing was applied to imaging of internal voids and reinforced steel bars in concrete material. The reconstruction of voids and steels in concrete specimen (400mm x 400mm x 400 mm) was demonstrated using a phased array transducer in the low frequency range. In this study, the array transducer with total 16 elements and center frequency of 50 kHz was developed. The volume fraction of aggregates in concrete was 70 %, and the maximum size of the coarse aggregate was 20 mm. Figure 1 shows the reconstruction result of a slit. For on-site inspection, we introduced a graphics processing unit (GPU) computation to accelerate the post-processing of beam-forming [2]. The flaw detection time was approximately 0.15 s using Geforce GTX880M (NVIDIA)

Distinguishability Measures and Entropies for General Probabilistic Theories

As a part of the construction of an information theory based on general probabilistic theories, we propose and investigate the several distinguishability measures and "entropies" in general probabilistic theories. As their applications, no-cloning theorems, information-disturbance theorems are reformulated, and a bound of the accessible informations is discussed in any general probabilistic theories, not resorting to quantum theory.Comment: 17 pages, 1 figure, Related but independent works (arXiv:0909.4801 and arXiv:0909.5075) have appeared recently while we were completing this paper. In v2, we added the reference (arXiv:0909.4801); In v3, "mimimum" is changed to "infimum" in the definition of fidelity so that it is more rigorou

Absence of germline mono-allelic promoter hypermethylation of the CDH1 gene in gastric cancer patients

<p>Abstract</p> <p>Background</p> <p>Germline mono-allelic promoter hypermethylation of the <it>MLH1 </it>or <it>MSH2 </it>gene in families with hereditary nonpolyposis colorectal cancer has recently been reported. The purpose of this study was to evaluate if germline promoter hypermethylation of the tumor suppressor gene <it>CDH1 </it>(<it>E-cadherin</it>) might cause predisposition to gastric cancer.</p> <p>Methods</p> <p>We prepared two groups of samples, a group of blood samples from 22 patients with familial gastric cancer or early-onset gastric cancer selected from among 39 patients, and a group of non-cancerous gastric tissue samples from 18 patients with sporadic gastric cancer showing loss of CDH1 expression selected from among 159 patients. We then investigated the allele-specific methylation status of the <it>CDH1 </it>promoter by bisulfite sequencing of multiple clones.</p> <p>Results</p> <p>Although there was a difference between the methylation level of the two alleles in some samples, there was no mono-allelic promoter hypermethylation in any of the samples.</p> <p>Conclusion</p> <p>These results suggest that germline mono-allelic hypermethylation of the <it>CDH1 </it>promoter is not a major predisposing factor for gastric cancer.</p