104 research outputs found
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 identically polarized photons is 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
Morfologia dos pré-estômagos e de papilas ruminais de cordeiras Santa Inês em crescimento submetidas a dois planos nutricionais
Efeito da adição de butirato de sódio, propionato de cálcio ou monensina sódica no concentrado inicial sobre parâmetros ruminais e de desenvolvimento do rúmen de bezerros leiteiros
Small-scale gene duplications played a major role in the recent evolution of wheat chromosome 3B
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