Nonlinear behavior of geometric phases induced by photon pairs

In this study, we observe the nonlinear behavior of the two-photon geometric phase for polarization states using time-correlated photons pairs. This phase manifests as a shift of two-photon interference fringes. Under certain arrangements, the geometric phase can vary nonlinearly and become very sensitive to a change in the polarization state. Moreover, it is known that the geometric phase for $N$ identically polarized photons is $N$ times larger than that for one photon. Thus, the geometric phase for two photons can become two times more sensitive to a state change. This high sensitivity to a change in the polarization can be exploited for precision measurement of small polarization variation. We evaluate the signal-to-noise ratio of the measurement scheme using the nonlinear behavior of the geometric phase under technical noise and highlight the practical advantages of this scheme.Comment: 10 pages, 10 figure

Geometrical aspects of weak measurements and quantum erasers

We investigate the mechanism of weak measurement by using an interferometric framework. In order to appropriately elucidate the interference effect that occurs in weak measurement, we introduce an interferometer for particles with internal degrees of freedom. It serves as a framework common to quantum eraser and weak measurement. We demonstrate that the geometric phase, particularly the Pancharatnam phase, results from the post-selection of the internal state, and thereby the interference pattern is changed. It is revealed that the extraordinary displacement of the probe wavepackets in weak measurement is achieved owing to the Pancharatnam phase associated with post-selection.Comment: 11 pages, 4 figure

Weak Values with Decoherence

The weak value of an observable is experimentally accessible by weak measurements as theoretically analyzed by Aharonov et al. and recently experimentally demonstrated. We introduce a weak operator associated with the weak values and give a general framework of quantum operations to the W operator in parallel with the Kraus representation of the completely positive map for the density operator. The decoherence effect is also investigated in terms of the weak measurement by a shift of a probe wave function of continuous variable. As an application, we demonstrate how the geometric phase is affected by the bit flip noise.Comment: 17 pages, 3 figure

Observation of geometric phases in quantum erasers

We introduce a simple experiment involving a double-slit interferometer by which one can learn basic concepts of quantum interference such as which-path marking, quantum erasers, and geometric phases. Each of them exhibits seemingly mysterious phenomena in quantum physics. In our experiment, we use the double-slit interference of visible light with the polarization as an internal state to demonstrate the disappearance of fringes by which-path marking, recovery of interference using quantum erasers, and the rapid shifting of the fringe pattern induced by the geometric phase. We also present a simple theoretical analysis of an interferometer with an internal state.Comment: 7 pages, 14 figure

Evidence for Female-Biased Dispersal in the Protandrous Hermaphroditic Asian Seabass, Lates calcarifer

Movement of individuals influences individual reproductive success, fitness, genetic diversity and relationships among individuals within populations and gene exchange among populations. Competition between males or females for mating opportunities and/or local resources predicts a female bias in taxa with monogamous mating systems and a male-biased dispersal in polygynous species. In birds and mammals, the patterns of dispersal between sexes are well explored, while dispersal patterns in protandrous hermaphroditic fish species have not been studied. We collected 549 adult individuals of Asian seabass (Lates calcarifer) from four locations in the South China Sea. To assess the difference in patterns of dispersal between sexes, we genotyped all individuals with 18 microsatellites. Significant genetic differentiation was detected among and within sampling locations. The parameters of population structure (FST), relatedness (r) and the mean assignment index (mAIC), in combination with data on tagging-recapture, supplied strong evidences for female-biased dispersal in the Asian seabass. This result contradicts our initial hypothesis of no sex difference in dispersal. We suggest that inbreeding avoidance of females, female mate choice under the condition of low mate competition among males, and male resource competition create a female-biased dispersal. The bigger body size of females may be a cause of the female-biased movement. Studies of dispersal using data from DNA markers and tagging-recapture in hermaphroditic fish species could enhance our understanding of patterns of dispersal in fish

Healable Cellulose Iontronic Hydrogel Stickers for Sustainable Electronics on Paper

The authors acknowledge the support from FCT - Portuguese Foundation for Science and Technology through the Ph.D. scholarships SFRH/BD/126409/2016 (I.C.) and SFRH/BD/122286/2016 (J.M.). The authors would like to acknowledge the European Commission under project NewFun (ERC-StG-2014, GA 640598) and project SYNERGY (H2020-WIDESPREAD-2020-5, CSA, proposal no 952169). This work was also supported by the FEDER funds through the COMPETE 2020 Program and the National Funds through the FCT - Portuguese Foundation for Science and Technology under the Project No. POCI-01-0145-FEDER-007688, reference UID/CTM/50025, project CHIHC, reference PTDC/NAN-MAT/32558/2017. The authors would also like to thank their colleagues Daniela Gomes and Ana Pimentel from CENIMAT/i3N for the SEM and DSC-TGA measurements, respectively.Novel nature-based engineered functional materials combined with sustainable and economically efficient processes are among the great challenges for the future of mankind. In this context, this work presents a new generation of versatile flexible and highly conformable regenerated cellulose hydrogel electrolytes with high ionic conductivity and self-healing ability, capable of being (re)used in electrical and electrochemical devices. They can be provided in the form of stickers and easily applied as gate dielectric onto flexible indium–gallium–zinc oxide transistors, decreasing the manufacturing complexity. Flexible and low-voltage (<2.5 V) circuits can be handwritten on-demand on paper transistors for patterning of conductive/resistive lines. This user-friendly and simplified manufacturing approach holds potential for fast production of low-cost, portable, disposable/recyclable, and low-power ion-controlled electronics on paper, making it attractive for application in sensors and concepts such as the “Internet-on-Things.”.publishersversionpublishe