Narrow Results

To address the problem of sources and sinks of atmospheric CO₂, measurements are needed on a global scale. Satellite instruments show promise, but typically measure the total column. Since sources and sinks at the surface represent a small perturbation to the total column, a precision of better than 1% is required. No species has ever been measured from space at this level. Over the last three years, we have developed a small instrument based upon a Fabry-Perot interferometer that is highly sensitive to atmospheric CO₂. We have tested this instrument in a ground based configuration and from aircraft platforms simulating operation from a satellite. The instrument is characterized by high signal to noise ratio, fast response and great specificity. We have performed simulations and instrument designs for systems to detect, H₂O, CO, ¹³CO₂, CH₄, CH₂O, NH₃, SO₂, N₂O, NO₂, and O₃. The high resolution and throughput, and small size of this instrument make it adaptable to many other atmospheric species. We present results and discuss ways this instrument can be used for ground, aircraft or space based surveillance and the detection of pollutants, toxics and industrial effluents in a variety of scenarios including battlefields, industrial monitoring, or pollution transport.

The Array for Microwave Background Anisotropy is a 7-element interferometer to be sited on Mauna Loa, Hawaii. The seven 1.2m telescopes are mounted on a 6-meter platform, and operates at 3mm wavelength. At the time of this meeting, the telescope is under construction at the Vertex factory in Germany. It is due to be delivered in the middle of 2004. A 2-element prototype instrument has already been deployed to Mauna Loa where initial tests are underway.

The Array for Microwave Background Anisotropy is a 7-element interferometer sited on Mauna Loa, Hawaii. The seven 60cm telescopes are mounted on a 6-meter platform, and operates at 3mm wavelength. In October 2006, the telescope was officially dedicated and renamed as the Y. T. Lee AMiBA. During 2007, scientific operations have begun, after a long process of calibration and testing. At the time of this meeting, six clusters of galaxies have been detected and mapped via the inverse Compton scattering of the Cosmic Microwave Background radiation, also known as the Sunyaev-Zel'dovich Effect.

Lowest-order cumulants provide important information on the shape of the emission source in femtoscopy. For the simple case of noninteracting identical particles, we show how the fourth-order source cumulant can be determined from measured cumulants in momentum space. The textbook Gram–Charlier series is found to be highly inaccurate, while the related Edgeworth series provides increasingly accurate estimates. Ordering of terms compatible with the Central Limit Theorem appears to play a crucial role even for non-Gaussian distributions.

In this paper, the advantages of pion versus kaon interferometry as a measure to probe the degree of source coherence are studied by a expanding boson gas model with a harmonic oscillator potential. We investigate the conditions about occurrence of Bose–Einstein condensation and analyze its impacts on the chaotic parameter λ. The results indicate that this finite condensation for pion system decreases the value of λ, but influence slightly for kaon system.

If there is a population of black holes distributed randomly in space, light rays passing in their vicinity will acquire random phases. In the “two-slit” model of an interferometer this can, for a high density of black holes, lead to a diffusion in the phase difference between the two arms of the interferometer and thus to a loss of coherence or “visibility” in interferometric observations. Hence the existence of “fringe contrast” or “visibility” in interferometric observations can be used to put a limit on the possible presence of black holes along the flight path. We give a formula for this effect and consider its application, particularly for observations in cosmology. Under the assumption that the dark matter consists of primordial black holes, we consider sources at high $z$, up to the CMB. While the strongest results are for the CMB as the most remote source, more nearby sources at high $z$ lead to similar effects. The effect increases with the baseline, and in the limiting case of the CMB we find that with earth-size baselines a nonzero “visibility” would limit the mass of possible primordial black holes, to approximately $M∕M_{\odot }\le 10^{-1}$. Although such limits would not appear to be as strong as those obtained, say from microlensing, they involve a much different methodology and are dominated by very early times (see Table 1). Longer baselines lead to more stringent limits and in principle with extreme lengths, the method could possibly find positive evidence for primordial black holes. In this case, however, all other kinds of phase averaging would have to be constrained or eliminated.

In this paper, we present a new design of the interferometer, intended for high-precision measurements of electric fields. We combined both arms of the interferometer in one segment of the fiber and the electric field sensor. The interferometer made using this scheme has a high resistance to mechanical and thermal fluctuations.

As an important part of laser interferometry system, optical bench is one of the core technologies for the detection of spaceborne gravitational waves. As the first step of the space Taiji program, Taiji-1 provides the measurement accuracy of laser interferometry system better than 100 pm/Hz${}^{1/2}$(@10 mHz–1 Hz). Taiji-1 is required to be able to track the motion of test mass in inertial sensor. According to the requirements, four interfering optical paths were designed. By adopting an integrated satellite design and selecting the optical and mechanical materials with low linear expansion coefficient, the high stability of optical path was achieved. By using the DOE method, the alignment errors (position/attitude) of four optical paths were all reduced to below 50 $\mu$ m/100 $\mu$ rad. In the performance test, the accuracy of laser interferometry system was better than 100 pm/Hz${}^{1/2}$(@10 mHz–1 Hz), and the modulation signal of inertial sensor was successfully detected. The results show that all technical indexes of optical bench have met or exceeded the design requirements.

The behavior of translationally–internally entangled (TIE) states in an interferometer of the Mach–Zehnder type is studied, by means of a game whose results show that TIE states allow near-certain guessing of both path (corpuscular) and phase (wavelike) features, as opposed to conventional states that are constrained by standard complementarity.

In this paper, we explore the dynamics of quantum correlations in an isolated physical quantum under the influence of intrinsic coherence. We characterize the quantum correlations in the hybrid system using the granular model to investigate the amount of coherent-chaotic fractions, and we particularly use the spherical droplets to measure the specific correlations. Likewise, we examine the effect of coherence on the source evolution of these quantifiers within engineering applications. In particular, the behavior of the multiparticle correlations in terms of the system parameters and the coherence rate is investigated and analyzed in detail to explore the source intrinsic dimensions. We found that the correlations with genuine interferences behave slightly unsymmetrical for identical parameters characterizing the considered complex system and that the genuine correlations are more meaningful than primary interference which probed the chaotic peculiarities against the coherence phenomena. Our results also show that the robustness of quantum correlations can be modulated by adjusting the coherent rate, source physical properties and the initial conditions.

We analyze a simple model of a scalar optical wave with partial coherence. The model is devised to describe the influence on the coherence of the wave, of the statistical properties of its random phase, including both the second-order statistics (phase correlation) — which is classic, but also the first-order statistics (phase distribution) — which is nonclassic. Expectedly, upon increasing the disorder of the fluctuating phase through a reduction of its correlation duration, the model shows that the coherence of the wave is always reduced. By contrast, upon increasing the disorder of the fluctuating phase through an increase of its dispersion, the model reveals that the coherence of the wave can sometimes be enhanced. This beneficial consequence of an increase in disorder is related to the phenomenon of stochastic resonance or improvement by noise in signal processing.

Out-of-equilibrium statistical mechanics is attracting considerable interest due to the recent advances in the control and manipulations of systems at the quantum level. Recently, an interferometric scheme for the detection of the characteristic function of the work distribution following a time-dependent process has been proposed [L. Mazzola et al., Phys. Rev. Lett.110 (2013) 230602]. There, it was demonstrated that the work statistics of a quantum system undergoing a process can be reconstructed by effectively mapping the characteristic function of work on the state of an ancillary qubit. Here, we expand that work in two important directions. We first apply the protocol to an interesting specific physical example consisting of a superconducting qubit dispersively coupled to the field of a microwave resonator, thus enlarging the class of situations for which our scheme would be key in the task highlighted above. We then account for the interaction of the system with an additional one (which might embody an environment), and generalize the protocol accordingly.

Finite element analysis is increasingly being used to model stresses in electronic assemblies. While numerical modelling tools have improved over the years, there is a need to validate models for more accurate and realistic stress-strain predictions. Owing to the scale and intricacy of the geometries involved, few techniques offer the spatial and strain resolution necessary to verify such models. This paper outlines, through a case study, the use of electronics speckle pattern interferometry to verify finite element modelling results by displacement correlation.

To increase the application potential in manufacturing process, such as monitoring the processing performance, the profile measurement should be provided in real-time display and with high resolution simultaneously. We propose a line-field Fourier-domain interferometric method (LFI), which combines the line-field microscope with spectral interferometer, for the surface cross-sectional profile measurement with no scan needed. The white light and objectives are employed to offer high axial and lateral resolution, respectively. In our system setup, the measurement could be implemented in real-time display of 10 frame/s, and the resolutions of the LFI system in X,Y, and Z directions are ~8 μm, ~3.2 μm, and ~1.4 μm, respectively. As a demonstration, the cross-sectional profiles of a microfluidic chip are tested. The graphics processing unit is also used to accelerate the reconstruction algorithm to achieve the real-time display of the cross-sectional profiles.

Measurement of the difference of the decay times of neutral kaon pairs produced in an antisymmetric entangled state allows for the search of possible violation of CPT symmetry and Lorentz invariance. In this paper we present the recently announced results based on the reaction ϕ → K_SK_L → π⁺π^-π⁺π^- measured at the KLOE experiment. Obtained parameters in the Standard Model Extension (SME) are:

After nearly one and a half centuries of effort, one of the most pernicious problems in observational astronomy — obtaining resolved images of the stars — is finally yielding to advances in modern instrumentation. The exquisite precision delivered by today's interferometric observatories is rapidly being applied to more and more branches of optical astronomy. The most capable interferometers in the Northern Hemisphere, both located in the United States are the Navy Precision Optical Interferometer (NPOI) in Arizona and the Center for High Angular Resolution Astronomy Array (CHARA) run by Georgia State University and located in California. In early 2013 these two groups held a joint meeting hosted by the Lowell Observatory in Flagstaff. All major groups working in the field were represented at this meeting and it was suggested to us by this Journal that this was an excellent opportunity to put together a special issue on interferometry. In order to be as broad as possible, those who did not attend the CHARA/NPOI meeting were also solicited to make a contribution. The result is this collection of papers representing a snap shot of the state of the art of ground based optical and near infrared interferometry.

We describe the data flow in the operation of the VEGA/CHARA instrument. After a brief summary of the main characteristics and scientific objectives of the VEGA instrument, we explain the standard procedure from the scientific idea up to the execution of the observation. Then, we describe the different steps done after the observation, from the raw data to the archives and the final products. Many tools are used and we show how the Virtual Observatory principles have been implemented for the interoperability of these software and databases.

In the same way that every telescope has multiple instruments and cameras, an interferometric array like the CHARA Array will have numerous beam combiners at the back end. And like the instruments of a single telescope, each of these combiners will be optimized for a particular kind of observation or scientific program. In this paper we describe the CLASSIC and CLIMB beam combiners of the CHARA Array. Both are open air, aperture plane, wide bandwidth single spectral channel instruments optimized for sensitivity. CLASSIC is the original two beam combiner used for the first science at CHARA, and it still has the faintest magnitude limit. CLIMB is a three beam expansion of CLASSIC that can also provide closure phase measurements.

In this paper, we present a new concept of instrument for high resolution imaging in astronomy, involving the sum frequency generation in non-linear waveguides. The aim is to convert the infrared radiation emitted by an astronomical source to the visible spectral domain where the optical components are mature and efficient. We present the main experimental results obtained in laboratory, and propose a new design for this instrument for its implementation on the Center for High Angular Resolution Astronomy (CHARA) telescope array. Preliminary stability and photometric results obtained at CHARA are presented. Using these last measurements, we estimate the limiting magnitudes which could be reached by this interferometer in the H spectral band.

The Amsterdam–ASTRON Radio Transients Facility and Analysis Center (AARTFAAC) all-sky monitor is a sensitive, real-time transient detector based on the Low Frequency Array (LOFAR). It generates images of the low frequency radio sky with spatial resolution of tens of arcmin, MHz bandwidths, and a time cadence of a few seconds, while simultaneously but independently observing with LOFAR. The image timeseries is then monitored for short and bright radio transients. On detection of a transient, a low latency trigger will be generated for LOFAR, which can interrupt its schedule to carry out follow-up observations of the trigger location at high sensitivity and resolutions. In this paper, we describe our heterogeneous, hierarchical design to manage the 259Gbps raw data rate and large scale computing to produce real-time images with minimum latency. We discuss the implementation of the instrumentation, its performance and scalability.