Michelson-Morley analogue for electrons using trapped ions to test Lorentz symmetry.

All evidence so far suggests that the absolute spatial orientation of an experiment never affects its outcome. This is reflected in the standard model of particle physics by requiring all particles and fields to be invariant under Lorentz transformations. The best-known tests of this important cornerstone of physics are Michelson-Morley-type experiments verifying the isotropy of the speed of light. For matter, Hughes-Drever-type experiments test whether the kinetic energy of particles is independent of the direction of their velocity, that is, whether their dispersion relations are isotropic. To provide more guidance for physics beyond the standard model, refined experimental verifications of Lorentz symmetry are desirable. Here we search for violation of Lorentz symmetry for electrons by performing an electronic analogue of a Michelson-Morley experiment. We split an electron wave packet bound inside a calcium ion into two parts with different orientations and recombine them after a time evolution of 95 milliseconds. As the Earth rotates, the absolute spatial orientation of the two parts of the wave packet changes, and anisotropies in the electron dispersion will modify the phase of the interference signal. To remove noise, we prepare a pair of calcium ions in a superposition of two decoherence-free states, thereby rejecting magnetic field fluctuations common to both ions. After a 23-hour measurement, we find a limit of h × 11 millihertz (h is Planck's constant) on the energy variations, verifying the isotropy of the electron's dispersion relation at the level of one part in 10(18), a 100-fold improvement on previous work. Alternatively, we can interpret our result as testing the rotational invariance of the Coulomb potential. Assuming that Lorentz symmetry holds for electrons and that the photon dispersion relation governs the Coulomb force, we obtain a fivefold-improved limit on anisotropies in the speed of light. Our result probes Lorentz symmetry violation at levels comparable to the ratio between the electroweak and Planck energy scales. Our experiment demonstrates the potential of quantum information techniques in the search for physics beyond the standard model.

New Methods for Testing Lorentz Invariance with Atomic Systems.

We describe a broadly applicable experimental proposal to search for the violation of local Lorentz invariance (LLI) with atomic systems. The new scheme uses dynamic decoupling and can be implemented in current atomic clock experiments, with both single ions and arrays of neutral atoms. Moreover, the scheme can be performed on systems with no optical transitions, and therefore it is also applicable to highly charged ions which exhibit a particularly high sensitivity to Lorentz invariance violation. We show the results of an experiment measuring the expected signal of this proposal using a two-ion crystal of ^{88}Sr^{+} ions. We also carry out a systematic study of the sensitivity of highly charged ions to LLI to identify the best candidates for the LLI tests.

Revealing Quantum Statistics with a Pair of Distant Atoms.

Quantum statistics have a profound impact on the properties of systems composed of identical particles. At the most elementary level, Bose and Fermi quantum statistics differ in the exchange phase, either 0 or π, which the wave function acquires when two identical particles are exchanged. In this Letter, we demonstrate that the exchange phase can be directly probed with a pair of massive particles by physically exchanging their positions. We present two protocols where the particles always remain spatially well separated, thus ensuring that the exchange contribution to their interaction energy is negligible and that the detected signal can only be attributed to the exchange symmetry of the wave function. We discuss possible implementations with a pair of trapped atoms or ions.

Systemic inflammatory response due to chloroform intoxication--an uncommon complication.

Well-known adverse effects of chloroform are drowsiness, nausea, and liver damage. Two cases with an uncommon complication due to chloroform intoxication are presented. In the first case, a general physician, because of nausea and dyspnea, admitted a 34-year-old woman to hospital. She developed a toxic pulmonary edema requiring mechanical ventilation for a few days, and a systemic inflammatory response syndrome (SIRS) with elevated white blood cell counts, a moderate increase of C-reactive protein, and slightly elevated procalcitonin levels. There were inflammatory altered skin areas progressing to necrosis later on. However, bacteria could be detected neither in blood culture nor in urine. Traces of chloroform were determined from a blood sample, which was taken 8 h after admission. Later, the husband confessed to the police having injected her chloroform and put a kerchief soaked with chloroform over her nose and mouth. In the second case, a 50-year-old man ingested chloroform in a suicidal attempt. He was found unconscious in his house and referred to a hospital. In the following days, he developed SIRS without growth of bacteria in multiple blood cultures. He died several days after admission due to multi-organ failure. SIRS in response to chloroform is a rare but severe complication clinically mimicking bacterial-induced sepsis. The mechanisms leading to systemic inflammation after chloroform intoxication are currently unclear. Possibly, chloroform and/or its derivates may interact with pattern recognition receptors and activate the same pro-inflammatory mediators (cytokines, interleukins, prostaglandins, leukotrienes) that cause SIRS in bacterial sepsis.

Collective quantum jumps of Rydberg atoms.

We study an open quantum system of atoms with a long-range Rydberg interaction, laser driving, and spontaneous emission. Over time, the system occasionally jumps between a state of low Rydberg population and a state of high Rydberg population. The jumps are inherently collective, and in fact, exist only for a large number of atoms. We explain how entanglement and quantum measurement enable the jumps, which are otherwise classically forbidden.

Scalable multiparticle entanglement of trapped ions.

The generation, manipulation and fundamental understanding of entanglement lies at the very heart of quantum mechanics. Entangled particles are non-interacting but are described by a common wavefunction; consequently, individual particles are not independent of each other and their quantum properties are inextricably interwoven. The intriguing features of entanglement become particularly evident if the particles can be individually controlled and physically separated. However, both the experimental realization and characterization of entanglement become exceedingly difficult for systems with many particles. The main difficulty is to manipulate and detect the quantum state of individual particles as well as to control the interaction between them. So far, entanglement of four ions or five photons has been demonstrated experimentally. The creation of scalable multiparticle entanglement demands a non-exponential scaling of resources with particle number. Among the various kinds of entangled states, the 'W state' plays an important role as its entanglement is maximally persistent and robust even under particle loss. Such states are central as a resource in quantum information processing and multiparty quantum communication. Here we report the scalable and deterministic generation of four-, five-, six-, seven- and eight-particle entangled states of the W type with trapped ions. We obtain the maximum possible information on these states by performing full characterization via state tomography, using individual control and detection of the ions. A detailed analysis proves that the entanglement is genuine. The availability of such multiparticle entangled states, together with full information in the form of their density matrices, creates a test-bed for theoretical studies of multiparticle entanglement. Independently, 'Greenberger-Horne-Zeilinger' entangled states with up to six ions have been created and analysed in Boulder.

Deterministic quantum teleportation with atoms.

Teleportation of a quantum state encompasses the complete transfer of information from one particle to another. The complete specification of the quantum state of a system generally requires an infinite amount of information, even for simple two-level systems (qubits). Moreover, the principles of quantum mechanics dictate that any measurement on a system immediately alters its state, while yielding at most one bit of information. The transfer of a state from one system to another (by performing measurements on the first and operations on the second) might therefore appear impossible. However, it has been shown that the entangling properties of quantum mechanics, in combination with classical communication, allow quantum-state teleportation to be performed. Teleportation using pairs of entangled photons has been demonstrated, but such techniques are probabilistic, requiring post-selection of measured photons. Here, we report deterministic quantum-state teleportation between a pair of trapped calcium ions. Following closely the original proposal, we create a highly entangled pair of ions and perform a complete Bell-state measurement involving one ion from this pair and a third source ion. State reconstruction conditioned on this measurement is then performed on the other half of the entangled pair. The measured fidelity is 75%, demonstrating unequivocally the quantum nature of the process.

Realization of universal ion-trap quantum computation with decoherence-free qubits.

Any residual coupling of a quantum computer to the environment results in computational errors. Encoding quantum information in a so-called decoherence-free subspace provides means to avoid these errors. Despite tremendous progress in employing this technique to extend memory storage times by orders of magnitude, computation within such subspaces has been scarce. Here, we demonstrate the realization of a universal set of quantum gates acting on decoherence-free ion qubits. We combine these gates to realize the first controlled-NOT gate towards a decoherence-free, scalable quantum computer.

A regression model applied to gender-specific ethanol elimination rates from blood and breath measurements in non-alcoholics.

As elimination rates for alcohol are suggested to be gender specific, a novel regression model has been applied to estimate these rates for both men and women using experimentally measured data from 81 female and 96 male volunteers described in previous papers. Breath alcohol measurements were done with the Alcotest 7110 Evidential device and were coupled with concomitant sampling of venous blood. Statistical analyses involved use of a mixed linear model for blood alcohol concentration (BAC) and breath alcohol concentration (BrAC), respectively. The model takes regression lines for each test subject into account with an individual starting value (2 h after the end of drinking) and with an individual alcohol elimination rate per hour (coincidental effects). Further, the data was modeled so that an average alcohol elimination rate per hour could be estimated separately for both genders (constant effects). This enables us to methodically correctly estimate the back calculation. The elimination rates beta (60), which can be used for minimum and maximum back calculations for the BAC, were 0.115 g/kg/h and 0.260 g/kg/h, respectively, for women and 0.096 g/kg/h and 0.241 g/kg/h, respectively, for men. These figures widely deviate from gender-unspecific values commonly used in Germany (0.1 and 0.2 g/kg/h, respectively). The corresponding values for the BrAC were 0.061 mg/l/h and 0.124 mg/l/h for women and 0.049 mg/l/h and 0.112 mg/l/h for men. The probability of an over- or underestimation of the abovementioned extreme values is 0.3% in each case.

[Perioperative fatal bleeding: link between acetabular anchoring of a cementless implant]. / Perioperative tödliche Blutungskomplikation: Lagebeziehung zwischen azetabulären Verankerungen einer zementfreien Hüftpfanne und den Iliakalgefässen.

This case report concerns a 75-year-old patient who suffered haemorrhagic shock and mors in tabula during implantation of a total hip arthroplasty. The cause was established as an injury of the external iliac vein, probably as a result of the predrilling of holes for the anchoring screws and pegs. The surgical method and topographic anatomy of the operating area are presented. Such vascular injuries are a rare but life-threatening complication of this procedure; the literature quotes a frequency of about 0.3%. So far, no fulminate venous bleeding process has been reported. Complications in such operations cannot always be avoided. However, detailed knowledge of the acetabular geometry can provide more safety for the surgeon when carrying out the secondary anchoring of a press-fit implant.

Local probe of single phonon dynamics in warm ion crystals.

The detailed characterization of non-trivial coherence properties of composite quantum systems of increasing size is an indispensable prerequisite for scalable quantum computation, as well as for understanding non-equilibrium many-body physics. Here, we show how autocorrelation functions in an interacting system of phonons as well as the quantum discord between distinct degrees of freedoms can be extracted from a small controllable part of the system. As a benchmark, we show this in chains of up to 42 trapped ions, by tracing a single phonon excitation through interferometric measurements of only a single ion in the chain. We observe the spreading and partial refocusing of the excitation in the chain, even on a background of thermal excitations. We further show how this local observable reflects the dynamical evolution of quantum discord between the electronic state and the vibrational degrees of freedom of the probe ion.

Cryogenic setup for trapped ion quantum computing.

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40Ca+ and 88Sr+ ions. The instability of the laser manipulating the optical qubits in 40Ca+ is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10-15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40Ca+ ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

Species differences in the handling of lysosomotropic metals and Triton WR 1339 by rat and Chinese hamster liver.

The study was undertaken in order to understand the reasons for the distinct differences in the elimination rate of lanthanides and transuranium elements from the liver of different mammalian species. The binding of monomeric 239Pu in livers of rats and Chinese hamsters was analyzed by density gradient centrifugation and electrophoresis. It was concluded that this nuclide is initially bound to lysosomes in liver of rats and Chinese hamsters. The influence of Triton WR 1339 (TWR) on the density of lysosomal marker enzymes from rat and Chinese hamster liver at day 4 was very similar for both animal species but the TWR induced shift persisted in Chinese hamsters up to day 60 whereas in rat liver the lysosomal density increased again with time. Electron microscopic inspection confirmed the similarity of the initial reaction of hepatocyte lysosomes. However, after 60 to 70 days typical TWR induced "tritosomes" were absent from rat hepatocytes but could be found regularly in hepatocytes from Chinese hamsters. The elimination rate of 3H-activity from liver injection of 3H-TWR was lower in Chinese hamsters than in rats. It was concluded that the differences in elimination rate of lanthanides and transuranium elements from liver of various mammalian species and the differences observed after TWR injection might reflect differences in the composition or function of the lysosomal system in the livers of different mammalian species. With respect to the transport of certain heavy metals the rat liver is not a reliable model for human liver.

Observation of the continuous stern-gerlach effect on an electron bound in an atomic Ion

We report on the first observation of the continuous Stern-Gerlach effect on an electron bound in an atomic ion. The measurement was performed on a single hydrogenlike ion ( 12C5+) in a Penning trap. The measured g factor of the bound electron, g = 2.001 042(2), is in excellent agreement with the theoretical value, confirming the relativistic correction at a level of 0.1%. This proves the possibility of g-factor determinations on atomic ions to high precision by using the continuous Stern-Gerlach effect. The result demonstrates the feasibility of conducting experiments on single heavy highly charged ions to test quantum electrodynamics in the strong electric field of the nucleus.

Effects of prepulses and d-amphetamine on performance and event-related potential measures on an auditory discrimination task.

RATIONALE: Prepulse inhibition (PPI) of the startle reflex is a measure of sensorimotor gating, that is the processing of the startle stimulus (S2) is inhibited by the interfering processing of a closely preceding prepulse (S1). It has been demonstrated that PPI is disrupted in a variety of mental disorders and that several neurotransmitter systems, including dopamine, participate in the modulation of sensorimotor gating. Previous studies have also shown that a task-relevant S1 enhances PPI in healthy subjects but not in schizophrenic patients. These findings indicate an influence of attentional processes on sensorimotor gating and an impairment of this modulation in schizophrenia. OBJECTIVE: Assuming a dopamine-mediated suppression of S1 processing as a mechanism of resource management and selective attention, which might be impaired in certain mental disorders, the present study investigated the effects of the indirect dopaminergic agonist d-amphetamine on prepulse-altered S2 discrimination and event related potentials (ERPs). METHODS: Twelve healthy volunteers were tested in a double-blind, placebo-controlled experimental design. Here, S2 is the target in a difficult Go/NoGo auditory discrimination task. RESULTS: Confirming our previous results, S2 processing is "accentuated" by a weak acoustic prepulse in healthy subjects, thus leading to a lower rate of errors of omission but also to more false alarms (i.e. a liberal response bias). This performance change correlated with a prepulse-induced increase in the amplitude of the P3 ERP towards non-targets ("prepulse-induced non-target positivity"; PINTP). In addition, the results of the present study show that under prepulse conditions amphetamine disrupts "S2 accentuation" associated with a dose-related reduction of the P2 component of the S1 response and a plasma level related reduction of PINTP. CONCLUSIONS: These data suggest an involuntary attentional shift towards S1 processing with increasing dopamine-release similar to that observed in patients with schizophrenia or OCD. It is concluded that sensory gating alters selective attention via dopaminergic modulation.

Comparative studies on the lysosomal association of monomeric 239Pu and 241Am in rat and Chinese hamster liver: analysis with sucrose, metrizamide, and Percoll density gradients of subcellular binding as dependent on time.

The binding of 239Pu and 241Am in the livers of Chinese hamsters and rats was analyzed by centrifugation of a mitochondrial-lysosomal fraction in sucrose, metrizamide, and Percoll density gradients at intervals between 4 and 70 days after nuclide injection. The behavior of 239Pu and 241Am during the centrifugation experiments was very similar. In contrast to the results for rats, the median densities of the nuclide profiles from hamsters decrease with time in hyperosmolar sucrose gradients, as does the nuclide fraction liberated by addition of Triton X-100, and the nuclide profiles do not respond typically to Triton WR 1339 treatment of the animals. The results with nearly iso- osmolar metrizamide gradients, together with those for Percoll, agree with the assumption that there is an initial lysosomal association of the transuranium elements. It was concluded from the results that the major fraction of 239Pu and 241Am remained bound to typical lysosomes in rat liver, whereas those in hamster liver may be transformed into telolysosomes . Possibly, a vesicular biliary transport system for certain heavy metals, for which evidence exists in rat liver, does not occur in Chinese hamster liver.

Therapeutic sleep deprivation in depressives, restricted to the two nocturnal hours between 3:00 and 5:00.

1. In 33 patients with a depressive syndrome the effects of partial SD restricted to the 2 hours between 3:00 and 5:00 in the morning was compared to that of no SD (= undisturbed sleep, n = 17) and total SD (n = 16) in a balanced crossover design. 2. Partial SD had a moderate antidepressant effect which is, however, clearly inferior to that of total SD. 3. Reasons for the scarceness of the effect may be an inappropriate timing of this 2-hr SD period (which seems improbable), too short a duration of SD, or the resumption of sleep at 5 o'clock. 4. "Intermediate" SD in the form it was used here represents no therapeutic advantage as we had expected. Its moderate effects lend support to the hypothesis that sleep disturbance is a sign of (mostly insufficient) restorative or self-healing efforts of the depressive organism.

Tentative injuries to exposed skin in a homicide case.

A 28-year-old man stabbed both his wife and his 3-year-old son to death, before unsuccessfully attempting to commit suicide. The incident occurred against a background of marital conflict. The child's body exhibited six tentative wounds to the skin in the area of the heart, with no corresponding defects in the overlying clothing, a pattern normally seen only in suicide. Their presence can be explained by the fact that this can be considered an extended suicide, the father's motivation for the killing being comparable to that for true suicide. However, wounds of this nature can be produced in such cases only if the victim is severely limited in his ability to defend himself, here due to the superior physical strength of the father.

Spleen findings in drowning.

A retrospective study of spleen findings in 42 victims of drowning and a comparison group of 42 cases of asphyxiation due to other causes (hanging, ligature strangulation and manual strangulation), that were matched for sex, age, body weight and build, was performed. Significantly smaller spleen weights (P < 0.05), spleen weight:body weight ratios (P < 0.01) and spleen weight:liver weight ratios (P < 0.01) were found in the victims of drowning. The difference in weight was approximately 18%. A significant negative correlation between spleen weight and blood alcohol concentration was found in the study group (r = -0.44; P < 0.01), but not in the control group. The possibility that the findings are due to a stress reaction caused by hypoxia in the presence of cooling and an influence of alcohol on reflex mechanisms is discussed.

Criteria for homicide and suicide on victims of extended suicide due to sharp force injury.

This report is about the findings in association with the extended suicides of nine victims killed by sharp force. All victims were killed by sharp force. The perpetrators were predominantly the parents, the victims their children. Regarding the criteria for differentiating self-inflicted injuries from injuries inflicted by another person, the victims' injuries presented patterns usually found solely in suicides. Thus eight of nine cases presented tentative and hesitation injuries, in three of five cases areas of injury covered by clothing had been exposed beforehand. Despite extremely narrow intercostal spaces in children, injuries to the bones in thoracic stabbing were avoided more often than not (four of seven cases). Only the criterion "defence injury" occurred nearly as often as in homicide victims (three of nine cases). The psychopathology of extended suicide can explain this pattern. The perpetrator's motive is characterised by his pseudoaltruistic belief to save the loved ones from a world that is in his opinion unacceptable. A fusion or integration of the victim into the perpetrator's own self is based on an identity problem. Physical interrelation of forces between perpetrator and victim restricts the victim in his defence and presents an important prerequisite for acquiring the patterns of described injuries.