Entanglement of Indistinguishable Particles

We present a general criterion for entanglement of N indistinguishable particles decomposed into arbitrary s subsystems based on the unambiguous measurability of correlation. Our argument provides a unified viewpoint on the entanglement of indistinguishable particles, which is still unsettled despite various proposals made mainly for the s = 2 case. Even though entanglement is defined only with reference to the measurement setup, we find that the so-called i.i.d. states form a special class of bosonic states which are universally separable.Comment: 6 pages, 3 figures, major revisio

Appendices for "Revisiting the Welfare Effects of Eliminating Business Cycles"

This paper offers several appendices for the article: the integration principle applied to the baseline model, the computational algorithm for the baseline model, calculating the welfare gain, algorithm for the model with short- and long-term unemployment, as well as additional result tables.

Dynamic predictive coding by the retina

Retinal ganglion cells convey the visual image from the eye to the brain. They generally encode local differences in space and changes in time rather than the raw image intensity. This can be seen as a strategy of predictive coding, adapted through evolution to the average image statistics of the natural environment. Yet animals encounter many environments with visual statistics different from the average scene. Here we show that when this happens, the retina adjusts its processing dynamically. The spatio-temporal receptive fields of retinal ganglion cells change after a few seconds in a new environment. The changes are adaptive, in that the new receptive field improves predictive coding under the new image statistics. We show that a network model with plastic synapses can account for the large variety of observed adaptations

Role of Frustration and Dimensionality in the Hubbard Model on the Stacked Square Lattice: Variational Cluster Approach

Using variational cluster approach, we study influence of frustration and dimensionality on magnetic properties in the ground state of Hubbard model on a stacked square lattice in the large $U$ region (U/t=10), by changing the next-nearest-neighbor hopping, $t^{\prime}$, and the interlayer hopping, $t_{\perp}$. For small $t_{\perp}<t^{\ast}_{\perp}$ with $t^{\ast}_{\perp}/t{\approx}0.44$, antiferromagnetic long-range order appears at small $t^{\prime}<t^{\prime}_{c_{1}}$, and collinear magnetic long-range order at large $t^{\prime}>t^{\prime}_{c_{2}}$. They are separated by a paramagnetic Mott insulating state which appears in the parameter region $t^{\prime}_{c_{1}}<t^{\prime}<t^{\prime}_{c_{2}}$. For large $t_{\perp}>t^{\ast}_{\perp}$, the paramagnetic Mott insulating state disappears and a direct transition between antiferromagnetic state and collinear magnetic state occurs at $t^{\prime}=t^{\prime}_{c_{3}}$. We also find that the transition from the antiferromagnetic state to the paramagnetic Mott insulating state is of the second-order and that from the collinear magnetic state to the paramagnetic Mott insulating or the antiferromagnetic state is of the first-order.Comment: 7 pages, 6 figures, submitted to Physical Review

Experimental Realization of a Relativistic Harmonic Oscillator

We report the experimental study of a harmonic oscillator in the relativistic regime. The oscillator is composed of Bose-condensed lithium atoms in the third band of an optical lattice, which have an energy-momentum relation nearly identical to that of a massive relativistic particle, with an effective mass reduced below the bare value and a greatly reduced effective speed of light. Imaging the shape of oscillator trajectories at velocities up to 98% of the effective speed of light reveals a crossover from sinusoidal to nearly photon-like propagation. The existence of a maximum velocity causes the measured period of oscillations to increase with energy; our measurements reveal beyond-leading-order contributions to this relativistic anharmonicity. We observe an intrinsic relativistic dephasing of oscillator ensembles, and a monopole oscillation with exactly the opposite phase of that predicted for non-relativistic harmonic motion. All observed dynamics are in quantitative agreement with longstanding but hitherto-untested relativistic predictions.Comment: 10 pages; 4 figure

The European Spallation Source neutrino super-beam conceptual design report

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA design study, named ESS νSB for European Spallation Source neutrino Super Beam, has been carried out during the years 2018–2022 of how the 5 MW proton linear accelerator of the European Spallation Source under construction in Lund, Sweden, can be used to produce the world’s most intense long-baseline neutrino beam. The high beam intensity will allow for measuring the neutrino oscillations near the second oscillation maximum at which the CP violation signal is close to three times higher than at the first maximum, where other experiments measure. This will enable CP violation discovery in the leptonic sector for a wider range of values of the CP violating phase δCP and, in particular, a higher precision measurement of δCP. The present Conceptual Design Report describes the results of the design study of the required upgrade of the ESS linac, of the accumulator ring used to compress the linac pulses from 2.86 ms to 1.2 μs, and of the target station, where the 5 MW proton beam is used to produce the intense neutrino beam. It also presents the design of the near detector, which is used to monitor the neutrino beam as well as to measure neutrino cross sections, and of the large underground far detector located 360 km from ESS, where the magnitude of the oscillation appearance of νe from νμ is measured. The physics performance of the ESS νSB research facility has been evaluated demonstrating that after 10 years of data-taking, leptonic CP violation can be detected with more than 5 standard deviation significance over 70% of the range of values that the CP violation phase angle δCP can take and that δCP can be measured with a standard error less than 8° irrespective of the measured value of δCP. These results demonstrate the uniquely high physics performance of the proposed ESS νSB research facilit

Changes of Gramine Contents as an Aphid Resistant Substance with Barley Growth

Barley plants may be severely damaged by aphids,mainly because they may transmit viruses,suck food and disrupt tissues. There are resistant lines and susceptible lines in barley to aphids. The changing amounts of gramine from seeding to mature stages were investigated on 27 lines from 1989 to 1991. Barley was sown aound November 20 in the year and harvested in early June. Higher amount of gramine in seeding stage in all lines were detected,then gradually decreased with barley growth until 2 to 3 weeks before the earing stages. At this time aphids had appeared on the barley leaves and increased in population. The susceptible lines had a tendency of greater decrease in gramine content than the resistant lines at the time of aphid population growth. The maximum aphid population was observed from the end of April to early May. The gramine content was almost constant this time. The degradation mechanisms may be important factors determining the defference of resistant and susceptible lines at the aphid population growth stage. The susceptible lines may have a higher activity of degradation mechanism.大麦はアブラムシ類の被害を受けることがある。ウイルス病の伝搬者として、また栄養分の掠奪者と組織細胞の破壊者として、害を及ぼしている。オオムギの系統の中にはアブラムシに対して、抵抗性の系統と感受性の系統がある。インドールアルカロイドであるグラミンはアブラムシを含む各種の動物に対して、毒性を有している。抵抗性と感受性の両者を含む27系統のオオムギについて、幼苗から成熟期迄のグラミン含量の変化を1989、1990、1991年の3年間にわたって調べた。オオムギは前年の11月20日頃播種し、翌年6月上旬に収穫した。全ての系統において幼苗は多量のグラミンを含有していた。抵抗性系統は感受性系統よりも多量に含有していた。この違いは、幼苗期においても成熟期におけるのと同じであった。全系統において、出穂前までの伸長生育期にグラミン含有は漸次減少した。4月初旬の減少し終わった時期に、アブラムシ類は飛来し、繁殖を始めた。4月下旬から5月上旬にアブラムシ類の密度は最高に達した。この時期に近づくに伴い抵抗性系統と感受性系統の明瞭な違いが見られ、グラミン含量の差も明瞭であった。グラミン含量は収穫まで余り変化せず、葉の老熟に伴う水分消失のため、単位重量当たりの換算値では多量になっていた。感受性系統は抵抗性系統に比べて、アブラムシ類が飛来し、繁殖する時期に、グラミンの分解が盛んで、少量のグラミンのみしか検出されなかった。分解に関与する機構が感受性系統では抵抗性系統よりも高いことが、系統間の差の大きな原因と推定された

Observation and uses of position-space Bloch oscillations in an ultracold gas

We report the direct observation and characterization of position-space Bloch oscillations using an ultracold gas in a tilted optical lattice. While Bloch oscillations in momentum space are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically too small to resolve. Tuning into the regime of rapid tunneling and weak force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.Comment: 5 pages, 6 figure