Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

During the past decade the interaction of light with multiatom ensembles has attracted much attention as a basic building block for quantum information processing and quantum state engineering. The field started with the realization that optically thick free space ensembles can be efficiently interfaced with quantum optical fields. By now the atomic ensemble-light interfaces have become a powerful alternative to the cavity-enhanced interaction of light with single atoms. Various mechanisms used for the quantum interface are discussed, including quantum nondemolition or Faraday interaction, quantum measurement and feedback, Raman interaction, photon echo, and electromagnetically induced transparency. This review provides a common theoretical frame for these processes, describes basic experimental techniques and media used for quantum interfaces, and reviews several key experiments on quantum memory for light, quantum entanglement between atomic ensembles and light, and quantum teleportation with atomic ensembles. The two types of quantum measurements which are most important for the interface are discussed: homodyne detection and photon counting. This review concludes with an outlook on the future of atomic ensembles as an enabling technology in quantum information processing.

Quantum interface between light and atomic ensembles

Understanding relaxation processes is an important unsolved problem in many areas of physics. A key challenge is the scarcity of experimental tools for the characterization of complex transient states. We used measurements of full quantum mechanical probability distributions of matter-wave interference to study the relaxation dynamics of a coherently split one-dimensional Bose gas and obtained comprehensive information about the dynamical states of the system. After an initial rapid evolution, the full distributions reveal the approach toward a thermal-like steady state characterized by an effective temperature that is independent from the initial equilibrium temperature of the system before the splitting process. We conjecture that this state can be described through a generalized Gibbs ensemble and associate it with prethermalization.

https://science.sciencemag.org/content/sci/337/6100/1318.full.pdf

Relaxation and Prethermalization in an Isolated Quantum System

Trapping and manipulating ultracold atoms and degenerate quantum gases in magnetic micropotentials is reviewed. Starting with a comprehensive description of the basic concepts and fabrication techniques of microtraps together with early pioneering experiments, emphasis is placed on current experiments on degenerate quantum gases. This includes the loading of quantum gases in microtraps, coherent manipulation, and transport of condensates together with recently reported experiments on matter-wave interferometry on a chip. Theoretical approaches for describing atoms in waveguides and beam splitters are briefly summarized, and, finally, the interaction between atoms and the surface of microtraps is covered in some detail.

Magnetic microtraps for ultracold atoms

A trapped-atom interferometer was demonstrated using gaseous Bose-Einstein condensates coherently split by deforming an optical single-well potential into a double-well potential. The relative phase between the two condensates was determined from the spatial phase of the matter wave interference pattern formed upon releasing the condensates from the separated potential wells. Coherent phase evolution was observed for condensates held separated by 13 microm for up to 5 ms and was controlled by applying ac Stark shift potentials to either of the two separated condensates.

/pdf/atom-interferometry-with-bose-einstein-condensates-in-a-33hik99t67.pdf

Atom Interferometry with Bose-Einstein Condensates in a Double-Well Potential

Atoms can be trapped and guided using nanofabricated wires on surfaces, achieving the scales required by quantum information proposals. These atom chips form the basis for robust and widespread application of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

Atoms and wires: toward atom chips

We present a versatile and compact electron beam driven source for alkali metal atoms, which can be implemented in cryostats. With a heat load of less than 10 mW, the heat dissipation normalized to the atoms loaded into the magneto-optical trap (MOT) is about a factor 1000 smaller than for a typical alkali metal dispenser. The measured linear scaling of the MOT loading rate with electron current observed in the experiments indicates that electron stimulated desorption is the corresponding mechanism to release the atoms.

Electron beam driven alkali metal atom source for loading a magneto-optical trap in a cryogenic environment

We present a versatile and compact electron beam driven source for alkali metal atoms, which can be implemented in cryostats. With a heat load of less than 10mW, the heat dissipation normalized to the atoms loaded into the magneto-optical Trap (MOT), is about a factor 1000 smaller than for a typical alkali metal dispenser. The measured linear scaling of the MOT loading rate with electron current observed in the experiments, indicates that electron stimulated desorption is the corresponding mechanism to release the atoms.

Der Einflus der praoperativen Diagnostik auf die Indikationsstellung beim Pankreaskarzinom ist unbestritten. Unklar bleibt aber die Wertigkeit der einzelnen Verfahren.

Leistungen der präoperativen Diagnostik für die Indikationsstellung beim Pankreaskarzinom

Soil has great biodiversity; edaphic fauna ranges from microscopic organisms (e.g., nematodes, mites) to those visible to the naked eye (e.g., earthworms, beetles, termites, ants), serving a range of essential ecosystem functions. However, soils are contaminated by anthropic activities such as mining, agriculture, industry, transport, and domestic discharges. These activities, which can release compounds such as pesticides, fertilizers, metals, and medicines into the environment (Edwards et al., 2018; Li et al., 2020; Zhu et al., 2018), negatively affect the health of organisms that inhabit the soil (Lisbôa et al., 2021), threatening the integrity of ecosystems globally. Thus, terrestrial ecotoxicology seeks to evaluate the effects of xenobiotic chemical substances on soil fauna. Niemeyer et al. (2017) identified the need to develop terrestrial ecotoxicological research to support regulatory refinements in Latin America (LA). These include developing environmental guidelines applicable to tropical and/or subtropical conditions and identifying and discerning the range of sensitivities of native test species to soil contaminants. Existing environmental legislation regarding soil quality standards and bioindicator species currently in use in LA are based on standards derived for North American or European countries. However, distinct climatic conditions (such as temperature and volume of precipitation), soil types, and native species in LA differ from those where these standards were developed. The lack of standardized methodologies for these ecologically distinct regions poses challenges for the realistic evaluation of risk to local ecosystems. Different environmental characteristics, such as biotic and abiotic factors, can influence the precision of ecotoxicological tests. Variables such as temperature, soil pH, mineralogy, organic matter content, and cation exchange capacity influence the availability, behavior, and persistence of contaminants present in the soil (Sarkar et al., 2022). These soil characteristics are profoundly influenced by climatic conditions and, therefore, soils from temperate and tropical regions have very different physicochemical characteristics. Countries that are located in different climatic regions of the world will have region‐specific contaminants, routes, effects, and organisms and conditions of exposure, and tests should reflect these differences. The differing structure and diversity of native communities in temperate versus tropical regions suggest that native species can better reflect potential sensitivity to effects of exposure in that environment. Earthworms are the group of organisms most used as bioindicators for the assessment of the quality of the terrestrial environment, as they are organisms of great relevance to the soil, have a wide spatial distribution, and are also considered easy to handle and breed. The guidelines of the Organization for Economic Co‐operation and Development (OECD) and the International Organization for Standardization (ISO) recommend the use of earthworm species Eisenia fetida and Eisenia andrei for the assessment of the effects of chemical substances on organisms (ISO, 2008, 2012; OECD, 1984, 2004). However, the earthworms E. fetida and E. andrei are native to temperate climates; the possible existence of more sensitive species for tropical and/ or subtropical regions needs to be evaluated (Lacher & Goldstein, 1997).

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/ieam.4737

Challenges and perspectives in terrestrial ecotoxicological assessment methodologies

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Atoms and wires: toward atom chips

Electron beam driven alkali metal atom source for loading a magneto-optical trap in a cryogenic environment

Electron beam driven alkali metal atom source for loading a magneto-optical trap in a cryogenic environment

Leistungen der präoperativen Diagnostik für die Indikationsstellung beim Pankreaskarzinom

Challenges and perspectives in terrestrial ecotoxicological assessment methodologies