There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

mirror, we use the evanescent wave that is formed by total internal reflection of a strong laser beam in a (glass) prism. The evanescent wave provides a strong intensity gradient, and thus combines a large potential with a very short interaction time, thereby limiting spontaneous emission even further. To reflect sodium atoms with a velocity of 1 m/s, at a detuning of 2 GHz, a laser intensity of -6 W/ cm' is required. To obtain a reasonable reflective area mirror, this means a laser power of -1 W is required, just barely within the range of commercial dye lasers. We achieve high laser intensities over a bigger spot sue by coupling the laser to a thin dielectric wave guide, that is deposited on a prism. Thus we obtain an evanescent wave which is a factor of 100-1000 stronger than would be the case for the bare prism.' We present the first measurements using such an enhanced evanescent wave as a mirror in which to reflect atoms at normal incidence. Sodium atoms are collected in a magneto-optical trap, cooled to -40 p K using polarization gradient cooling and then released to accelerate in the gravity field. The atomic mirror sits 1 M O mm under the trap, and reflects the atomic wave. The reflected atoms are detected in the trap region after their ballistic flight time. We report a large enhancement of the evanescent wave, observed by reflection of atoms dropped from a 10mm hei ht on a large area atomic mirror (10 mm) up until large detunings (10 GHz) using moderate amounts of laser power (500 mW). 'Institut d'Optique Thhorique et Appliqute, B.P. 147, F-91403 d'orsay, France

Guides for atoms

Physikern der Universitat Heidelberg ist es gelungen, mit einem Bose-Einstein-Kondensat (BEK) mit hoher Empfindlichkeit Magnetfelder zu messen Die neue Methode vereint hohe raumliche Auflosung von 3 μm mit einer sehr guten Sensitivitat im Bereich von Nanotesla

Bose-Einstein-Kondensat als Magnetfeldsensor

Quantum field theory is a powerful tool to describe the relevant physics governing complex quantum many-body systems. Here we develop a general pathway to extract the irreducible building blocks of quantum field theoretical descriptions and its parameters purely from experimental data. This is accomplished by extracting the one-particle irreducible (1PI) vertices from which one can construct all observables. To match the capabilities of experimental techniques used in quantum simulation experiments, our approach employs a formulation of quantum field theory based on equal-time correlation functions only. We illustrate our procedure by applying it to the quantum sine-Gordon model in thermal equilibrium. The theoretical foundations are illustrated by estimating the irreducible vertices at equal times both analytically and using numerical simulations. We then demonstrate explicitly how to extract these quantities from an experiment where we quantum simulate the sine-Gordon model by two tunnel-coupled superfluids. We extract the full two-point function and the interaction vertex (four-point function) and their variation with momentum, encoding the `running' of the couplings. The measured 1PI vertices are compared to the theoretical estimates, verifying our procedure. Our work opens new ways of addressing fundamental questions in quantum field theory, which are relevant in high-energy and condensed matter physics, and in taking quantum phenomena from fundamental science to practical technology.

Extracting the field theory description of a quantum many-body system from experimental data

Matter wave diffraction at periodic potentials made of light was first demonstrated in 1983 [1]. In Bragg diffraction, which is well known from X-ray scattering at solids, the interaction with a periodic potential is only weak and clearly shows wave properties. This effect was first observed with atoms at standing light waves in 1988 [2] and later studied in detail [3]. By increasing the light intensity one can realize higher potentials and can thus reach the regime of channeling, where now the atoms behave like particles and their propagation can be described with classical trajectories.

Matter Wave Diffraction at Standing Light Waves

We design a neural network to extract and process features from absorption images taken of one-dimensional Bose gases in the quasicondensate regime. Specifically, the network is trained to predict both the temperature of single realizations of the system and the uncertainty thereof. For multiple realizations, the individual predictions can be combined in an estimate of the mean temperature, improving precision. We benchmark our model on both simulated and experimentally measured data and compare it to the established method of density ripple thermometry. We find the predictions of the two methods compatible, although the neural network reaches similar precision needing many fewer realizations, thus highlighting the efficiency gain achievable when incorporating neural networks into analysis of data from cold gas experiments. Further, we study feature maps to reveal which local features of the condensate are extracted by the network and how said features correlate with properties of the system. A similar analysis could be employed to uncover physical relations in more complex systems.

Jörg Schmiedmayer

Papers

Guides for atoms

Bose-Einstein-Kondensat als Magnetfeldsensor

Extracting the field theory description of a quantum many-body system from experimental data

Matter Wave Diffraction at Standing Light Waves

Thermometry of one-dimensional Bose gases with neural networks