Heating and cooling in adiabatic mixing process
NASA Astrophysics Data System (ADS)
Zhou, Jing; Cai, Zi; Zou, Xu-Bo; Guo, Guang-Can
2010-12-01
We study the effect of interaction on the temperature change in the process of adiabatic mixing of two components of Fermi gases using the real-space Bogoliubov-de Gennes method. We find that in the process of adiabatic mixing, the competition between the adiabatic expansion and the attractive interaction makes it possible to cool or heat the system depending on the strength of the interaction and the initial temperature of the system. The changes of the temperature in a bulk system and in a trapped system are investigated.
Apparatus to Measure Adiabatic and Isothermal Processes.
ERIC Educational Resources Information Center
Lamb, D. W.; White, G. M.
1996-01-01
Describes a simple manual apparatus designed to serve as an effective demonstration of the differences between isothermal and adiabatic processes for the general or elementary physics student. Enables students to verify Boyle's law for slow processes and identify the departure from this law for rapid processes and can also be used to give a clear…
An integrated programming and development environment for adiabatic quantum optimization
NASA Astrophysics Data System (ADS)
Humble, T. S.; McCaskey, A. J.; Bennink, R. S.; Billings, J. J.; DʼAzevedo, E. F.; Sullivan, B. D.; Klymko, C. F.; Seddiqi, H.
2014-01-01
Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware has raised challenging questions about how to evaluate adiabatic quantum optimization (AQO) programs. Processor behavior depends on multiple steps to synthesize an adiabatic quantum program, which are each highly tunable. We present an integrated programming and development environment for AQO called Jade Adiabatic Development Environment (JADE) that provides control over all the steps taken during program synthesis. JADE captures the workflow needed to rigorously specify the AQO algorithm while allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation engine that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its potential use for benchmarking AQO programs by the quantum computer science community.
An Integrated Development Environment for Adiabatic Quantum Programming
Humble, Travis S; McCaskey, Alex; Bennink, Ryan S; Billings, Jay Jay; D'Azevedo, Eduardo; Sullivan, Blair D; Klymko, Christine F; Seddiqi, Hadayat
2014-01-01
Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware raises the question of how well quantum programs perform. Benchmarking behavior is challenging since the multiple steps to synthesize an adiabatic quantum program are highly tunable. We present an adiabatic quantum programming environment called JADE that provides control over all the steps taken during program development. JADE captures the workflow needed to rigorously benchmark performance while also allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation engine that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its use for benchmarking adiabatic quantum programs.
SIMULATION OF CONTINUOUS-CONTACT SEPARATION PROCESSES: MULTICOMPONENT, ADIABATIC ABSORPTION
A new algorithm has been developed for the steady-state simulation of multicomponent, adiabatic absorption in packed columns. The system of differential model equations that describe the physical absorption process is reduced to algebraic equations by using a finite difference me...
Differential topology of adiabatically controlled quantum processes
NASA Astrophysics Data System (ADS)
Jonckheere, Edmond A.; Rezakhani, Ali T.; Ahmad, Farooq
2013-03-01
It is shown that in a controlled adiabatic homotopy between two Hamiltonians, H 0 and H 1, the gap or "anti-crossing" phenomenon can be viewed as the development of cusps and swallow tails in the region of the complex plane where two critical value curves of the quadratic map associated with the numerical range of H 0 + i H 1 come close. The "near crossing" in the energy level plots happens to be a generic situation, in the sense that a crossing is a manifestation of the quadratic numerical range map being unstable in the sense of differential topology. The stable singularities that can develop are identified and it is shown that they could occur near the gap, making those singularities of paramount importance. Various applications, including the quantum random walk, are provided to illustrate this theory.
An Adiabatic Architecture for Linear Signal Processing
NASA Astrophysics Data System (ADS)
Vollmer, M.; Götze, J.
2005-05-01
Using adiabatic CMOS logic instead of the more traditional static CMOS logic can lower the power consumption of a hardware design. However, the characteristic differences between adiabatic and static logic, such as a four-phase clock, have a far reaching influence on the design itself. These influences are investigated in this paper by adapting a systolic array of CORDIC devices to be implemented adiabatically. We present a means to describe adiabatic logic in VHDL and use it to define the systolic array with precise timing and bit-true calculations. The large pipeline bubbles that occur in a naive version of this array are identified and removed to a large degree. As an example, we demonstrate a parameterization of the CORDIC array that carries out adaptive RLS filtering.
Adiabatic shear mechanisms for the hard cutting process
NASA Astrophysics Data System (ADS)
Yue, Caixu; Wang, Bo; Liu, Xianli; Feng, Huize; Cai, Chunbin
2015-05-01
The most important consequence of adiabatic shear phenomenon is formation of sawtooth chip. Lots of scholars focused on the formation mechanism of sawtooth, and the research often depended on experimental approach. For the present, the mechanism of sawtooth chip formation still remains some ambiguous aspects. This study develops a combined numerical and experimental approach to get deeper understanding of sawtooth chip formation mechanism for Polycrystalline Cubic Boron Nitride (PCBN) tools orthogonal cutting hard steel GCr15. By adopting the Johnson-Cook material constitutive equations, the FEM simulation model established in this research effectively overcomes serious element distortions and cell singularity in high strain domain caused by large material deformation, and the adiabatic shear phenomenon is simulated successfully. Both the formation mechanism and process of sawtooth are simulated. Also, the change features regarding the cutting force as well as its effects on temperature are studied. More specifically, the contact of sawtooth formation frequency with cutting force fluctuation frequency is established. The cutting force and effect of cutting temperature on mechanism of adiabatic shear are investigated. Furthermore, the effects of the cutting condition on sawtooth chip formation are researched. The researching results show that cutting feed has the most important effect on sawtooth chip formation compared with cutting depth and speed. This research contributes a better understanding of mechanism, feature of chip formation in hard turning process, and supplies theoretical basis for the optimization of hard cutting process parameters.
Novel developments and applications of the classical adiabatic dynamics technique
NASA Astrophysics Data System (ADS)
Rosso, Lula
The present work aims to apply and develop modern molecular dynamics techniques based on a novel analysis of the classical adiabatic dynamics approach. In the first part of this thesis, Car-Parrinello ab-initio molecular dynamics, a successful technique based on adiabatic dynamics, is used to study the charge transport mechanism in solid ammonium perchlorate (AP) crystal exposed to an ammonia-rich environment. AP is a solid-state proton conductor composed of NH+4 and ClO-4 units that can undergo a decomposition process at high temperature, leading to its use such as rocket fuel. After computing IR spectra and carefully analysing the dynamics at different temperatures, we found that the charge transport mechanism in the pure crystal is dominated by diffusion of the ammonium ions and that the translational diffusion is strongly coupled to rotational diffusion of the two types of ions present. When the pure ammonium-perchlorate crystal is doped with neutral ammonia, another mechanism comes into play, namely, the Grotthuss proton hopping mechanism via short-lived N2H+7 complexes. In the second part of this thesis, adiabatic dynamics will be used to develop an alternative approach to the calculation of free energy profiles along reaction paths. The new method (AFED) is based on the creation of an adiabatic separation between the reaction coordinate subspace and the remaining degrees of freedom within a molecular dynamics run. This is achieved by associating with the reaction coordinate(s) a high temperature and large mass. These conditions allow the activated process to occur while permitting the remaining degrees of freedom to respond adiabatically. In this limit, by applying a formal multiple time scale Liouville operator factorization, it can be rigorously shown that the free energy profile is obtained directly from the probability distribution of the reaction coordinate subspace and, therefore, no postprocessing of the output data is required. The new method is
Adiabatic and diabatic process of sum frequency conversion.
Liqing, Ren; Yongfang, Li; Baihong, Li; Lei, Wang; Zhaohua, Wang
2010-09-13
Based on the dressed state formalism, we obtain the adiabatic criterion of the sum frequency conversion. We show that this constraint restricts the energy conversion between the two dressed fields, which are superpositions of the signal field and the sum frequency field. We also show that the evolution of the populations of the dressed fields, which in turn describes the conversion of light photons from the seed frequency to the sum frequency during propagation through the nonlinear crystal. Take the quasiphased matched (QPM) scheme as an example, we calculate the expected bandwidth of the frequency conversion process, and its dependence on the length of the crystal. We demonstrate that the evolutionary patterns of the sum frequency field's energy are similar to the Fresnel diffraction of a light field. We finally show that the expected bandwidth can be also deduced from the evolution of the adiabaticity of the dressed fileds. PMID:20940935
Modeling of the Adiabatic and Isothermal Methanation Process
NASA Astrophysics Data System (ADS)
Porubova, Jekaterina; Bazbauers, Gatis; Markova, Darja
2011-01-01
Increased use of biomass offers one of the ways to reduce anthropogenic impact on the environment. Using various biomass conversion processes, it is possible to obtain different types of fuels: • solid, e.g. bio-carbon; • liquid, e.g. biodiesel and ethanol; • gaseous, e.g. biomethane. Biomethane can be used in the transport and energy sector, and the total methane production efficiency can reach 65%. By modeling adiabatic and isothermal methanation processes, the most effective one from the methane production point of view is defined. Influence of the process parameters on the overall efficiency of the methane production is determined.
Adiabatic Processes Realized with a Trapped Brownian Particle
NASA Astrophysics Data System (ADS)
Martínez, Ignacio A.; Roldán, Édgar; Dinis, Luis; Petrov, Dmitri; Rica, Raúl A.
2015-03-01
The ability to implement adiabatic processes in the mesoscale is of key importance in the study of artificial or biological micro- and nanoengines. Microadiabatic processes have been elusive to experimental implementation due to the difficulty in isolating Brownian particles from their fluctuating environment. Here we report on the experimental realization of a microscopic quasistatic adiabatic process employing a trapped Brownian particle. We circumvent the complete isolation of the Brownian particle by designing a protocol where both characteristic volume and temperature of the system are changed in such a way that the entropy of the system is conserved along the process. We compare the protocols that follow from either the overdamped or underdamped descriptions, demonstrating that the latter is mandatory in order to obtain a vanishing average heat flux to the particle. We provide analytical expressions for the distributions of the fluctuating heat and entropy and verify them experimentally. Our protocols could serve to implement the first microscopic engine that is able to attain the fundamental limit for the efficiency set by Carnot.
Adiabatic processes realized with a trapped Brownian particle.
Martínez, Ignacio A; Roldán, Édgar; Dinis, Luis; Petrov, Dmitri; Rica, Raúl A
2015-03-27
The ability to implement adiabatic processes in the mesoscale is of key importance in the study of artificial or biological micro- and nanoengines. Microadiabatic processes have been elusive to experimental implementation due to the difficulty in isolating Brownian particles from their fluctuating environment. Here we report on the experimental realization of a microscopic quasistatic adiabatic process employing a trapped Brownian particle. We circumvent the complete isolation of the Brownian particle by designing a protocol where both characteristic volume and temperature of the system are changed in such a way that the entropy of the system is conserved along the process. We compare the protocols that follow from either the overdamped or underdamped descriptions, demonstrating that the latter is mandatory in order to obtain a vanishing average heat flux to the particle. We provide analytical expressions for the distributions of the fluctuating heat and entropy and verify them experimentally. Our protocols could serve to implement the first microscopic engine that is able to attain the fundamental limit for the efficiency set by Carnot. PMID:25860731
Shortcuts to adiabaticity in classical and quantum processes for scale-invariant driving
NASA Astrophysics Data System (ADS)
Deffner, Sebastian; Jarzynski, Christopher; Del Campo, Adolfo
2014-03-01
All real physical processes in classical as well as in quantum devices operate in finite-time. For most applications, however, adiabatic, i.e. infinitely-slow processes, are more favorable, as these do not cause unwanted, parasitic excitations. A shortcut to adiabaticity is a driving protocol which reproduces in a short time the same final state that would result from an adiabatic process. A particular powerful technique to engineer such shortcuts is transitionless quantum driving by means of counterdiabatic fields. However, determining closed form expressions for the counterdiabatic field has generally proven to be a daunting task. In this paper, we introduce a novel approach, with which we find the explicit form of the counterdiabatic driving field in arbitrary scale-invariant dynamical processes, encompassing expansions and transport. Our approach originates in the formalism of generating functions, and unifies previous approaches independently developed for classical and quantum systems. We show how this new approach allows to design shortcuts to adiabaticity for a large class of classical and quantum, single-particle, non-linear, and many-body systems. SD and CJ acknowledge support from the National Science Foundation (USA) under grant DMR-1206971. This research is further supported by the U.S Department of Energy through the LANL/LDRD Program and a LANL J. Robert Oppenheimer fellowship (AdC).
Development of a semi-adiabatic isoperibol solution calorimeter
NASA Astrophysics Data System (ADS)
Venkata Krishnan, R.; Jogeswararao, G.; Parthasarathy, R.; Premalatha, S.; Prabhakar Rao, J.; Gunasekaran, G.; Ananthasivan, K.
2014-12-01
A semi-adiabatic isoperibol solution calorimeter has been indigenously developed. The measurement system comprises modules for sensitive temperature measurement probe, signal processing, data collection, and joule calibration. The sensitivity of the temperature measurement module was enhanced by using a sensitive thermistor coupled with a lock-in amplifier based signal processor. A microcontroller coordinates the operation and control of these modules. The latter in turn is controlled through personal computer (PC) based custom made software developed with LabView. An innovative summing amplifier concept was used to cancel out the base resistance of the thermistor. The latter was placed in the dewar. The temperature calibration was carried out with a standard platinum resistance (PT100) sensor coupled with an 8½ digit multimeter. The water equivalent of this calorimeter was determined by using electrical calibration with the joule calibrator. The experimentally measured values of the quantum of heat were validated by measuring heats of dissolution of pure KCl (for endotherm) and tris (hydroxyl methyl) amino-methane (for exotherm). The uncertainity in the measurements was found to be within ±3%.
Development of a semi-adiabatic isoperibol solution calorimeter
Venkata Krishnan, R.; Jogeswararao, G.; Parthasarathy, R.; Premalatha, S.; Prabhakar Rao, J.; Gunasekaran, G.; Ananthasivan, K.
2014-12-15
A semi-adiabatic isoperibol solution calorimeter has been indigenously developed. The measurement system comprises modules for sensitive temperature measurement probe, signal processing, data collection, and joule calibration. The sensitivity of the temperature measurement module was enhanced by using a sensitive thermistor coupled with a lock-in amplifier based signal processor. A microcontroller coordinates the operation and control of these modules. The latter in turn is controlled through personal computer (PC) based custom made software developed with LabView. An innovative summing amplifier concept was used to cancel out the base resistance of the thermistor. The latter was placed in the dewar. The temperature calibration was carried out with a standard platinum resistance (PT100) sensor coupled with an 8½ digit multimeter. The water equivalent of this calorimeter was determined by using electrical calibration with the joule calibrator. The experimentally measured values of the quantum of heat were validated by measuring heats of dissolution of pure KCl (for endotherm) and tris (hydroxyl methyl) amino-methane (for exotherm). The uncertainity in the measurements was found to be within ±3%.
NASA Astrophysics Data System (ADS)
Agostini, Federica; Abedi, Ali; Suzuki, Yasumitsu; Min, Seung Kyu; Maitra, Neepa T.; Gross, E. K. U.
2015-03-01
The Born-Oppenheimer (BO) approximation allows to visualize the coupled electron-nuclear dynamics in molecular systems as a set of nuclei moving on a single potential energy surface representing the effect of the electrons in a given eigenstate. Many interesting phenomena, however, such as vision or charge separation in organic photovoltaic materials, take place in conditions beyond its range of validity. Nevertheless, the basic construct of the adiabatic treatment, the BO potential energy surfaces, is employed to describe non-adiabatic processes and the full problem is represented in terms of adiabatic states and transitions among them in regions of strong non-adiabatic coupling. But the concept of single potential energy is lost. The alternative point of view arising in the framework of the exact factorization of the electron-nuclear wave function will be presented. A single, time-dependent, potential energy provides the force driving the nuclear motion and is adopted as starting point for the development of quantum-classical approximations to the full quantum mechanical problem.
Progress in the Development of a Continuous Adiabatic Demagnetization Refrigerator
NASA Technical Reports Server (NTRS)
Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Jackson, Michael; King, Todd; Tuttle, James; Krebs, Carolyn A. (Technical Monitor)
2002-01-01
We report on recent progress in the development of a continuous adiabatic demagnetization refrigerator (CADR). Continuous operation avoids the constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, allowing us to achieve an order of magnitude larger cooling power per unit mass. Our current design goal is 10 micro W of cooling at 50 mK using a 6-10 K heat sink. The estimated mass is less than 10 kg, including magnetic shielding of each stage. The relatively high heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long mission life and reduced complexity and cost. We have assembled a three-stage CADR and have demonstrated continuous cooling using a superfluid helium bath as the heat sink. The temperature stability is 8 micro K rms or better over the entire cycle, and the cooling power is 2.5 micro W at 60 mK rising to 10 micro W at 100 mK.
Cosmological consequences of an adiabatic matter creation process
NASA Astrophysics Data System (ADS)
Nunes, Rafael C.; Pan, Supriya
2016-06-01
In this paper, we investigate the cosmological consequences of a continuous matter creation associated with the production of particles by the gravitational field acting on the quantum vacuum. To illustrate this, three phenomenological models are considered. An equivalent scalar field description is presented for each models. The effects on the cosmic microwave background power spectrum are analysed for the first time in the context of adiabatic matter creation cosmology. Further, we introduce a model independent treatment, Om, which depends only on the Hubble expansion rate and the cosmological redshift to distinguish any cosmological model from Λ cold dark matter by providing a null test for the cosmological constant, meaning that, for any two redshifts z1, z2, Om(z) is same, i.e. Om(z1) - Om(z2) = 0. Also, this diagnostic can differentiate between several cosmological models by indicating their quintessential/phantom behaviour without knowing the accurate value of the matter density, and the present value of the Hubble parameter. For our models, we find that particle production rate is inversely proportional to Om. Finally, the validity of the generalized second law of thermodynamics bounded by the apparent horizon has been examined.
Orel, Ann E.; Miller, William H.
1980-11-01
A recently developed classical model for electronically nonadiabatic collision processes is applied to electronic-vibrational energy transfer in a collinear atom~diatom system, A + BC(v=1) + A*+ BC(v=0), which closely resembles Br-H{sub 2}. This classical model, which treats electronic as well as heavy particle (i.e., translation, rotation, and vibration) degrees of freedom by classical mechanics, is found to describe the resonance features in this process reasonably well. The usefulness of the approach is that it allows one to extend standard Monte Carlo classical trajectory methodology to include electronically non-adiabatic processes in a dynamically consistent way,
Parallelizable adiabatic gate teleportation
NASA Astrophysics Data System (ADS)
Nakago, Kosuke; Hajdušek, Michal; Nakayama, Shojun; Murao, Mio
2015-12-01
To investigate how a temporally ordered gate sequence can be parallelized in adiabatic implementations of quantum computation, we modify adiabatic gate teleportation, a model of quantum computation proposed by Bacon and Flammia [Phys. Rev. Lett. 103, 120504 (2009), 10.1103/PhysRevLett.103.120504], to a form deterministically simulating parallelized gate teleportation, which is achievable only by postselection. We introduce a twisted Heisenberg-type interaction Hamiltonian, a Heisenberg-type spin interaction where the coordinates of the second qubit are twisted according to a unitary gate. We develop parallelizable adiabatic gate teleportation (PAGT) where a sequence of unitary gates is performed in a single step of the adiabatic process. In PAGT, numeric calculations suggest the necessary time for the adiabatic evolution implementing a sequence of L unitary gates increases at most as O (L5) . However, we show that it has the interesting property that it can map the temporal order of gates to the spatial order of interactions specified by the final Hamiltonian. Using this property, we present a controlled-PAGT scheme to manipulate the order of gates by a control qubit. In the controlled-PAGT scheme, two differently ordered sequential unitary gates F G and G F are coherently performed depending on the state of a control qubit by simultaneously applying the twisted Heisenberg-type interaction Hamiltonians implementing unitary gates F and G . We investigate why the twisted Heisenberg-type interaction Hamiltonian allows PAGT. We show that the twisted Heisenberg-type interaction Hamiltonian has an ability to perform a transposed unitary gate by just modifying the space ordering of the final Hamiltonian implementing a unitary gate in adiabatic gate teleportation. The dynamics generated by the time-reversed Hamiltonian represented by the transposed unitary gate enables deterministic simulation of a postselected event of parallelized gate teleportation in adiabatic
NASA Astrophysics Data System (ADS)
Lengaigne, M.; Hausmann, U.; Madec, G.; Menkes, C.; Vialard, J.; Molines, J. M.
2012-03-01
Variations of the volume of warm water above the thermocline in the equatorial Pacific are a good predictor of ENSO (El Niño/Southern Oscillation) and are thought to be critical for its preconditioning and development. In this study, the Warm Water Volume (WWV) interannual variability is analysed using forced general circulation model experiments and an original method for diagnosing processes responsible for WWV variations. The meridional recharge/discharge to higher latitudes drives 60% of the ENSO-related equatorial WWV variations, while diabatic processes in the eastern equatorial Pacific account for the remaining 40%. Interior meridional transport is partially compensated by western boundary transports, especially in the southern hemisphere. Diabatic equatorial WWV formation (depletions) during La Niña (El Niño) are explained by enhanced (reduced) diathermal transport through enhanced (reduced) vertical mixing and penetrating solar forcing at the 20°C isotherm depth. The respective contribution of diabatic and adiabatic processes during build-ups/depletions strongly varies from event-to-event. The WWV build-up during neutral ENSO phases (e.g. 1980-1982) is almost entirely controlled by meridional recharge, providing a text-book example for the recharge/discharge oscillator's theory. On the other hand, diabatic processes are particularly active during the strongest La Niña events (1984, 1988, 1999), contributing to more than 70% of the WWV build-up, with heating by penetrative solar fluxes explaining as much as 30% of the total build-up due to a very shallow thermocline in the eastern Pacific. This study does not invalidate the recharge/discharge oscillator theory but rather emphasizes the importance of equatorial diabatic processes and western boundary transports in controlling WWV changes.
NASA Technical Reports Server (NTRS)
Serlemitsos, Aristides T.; Warner, Brent A.; Sansebastian, Marcelino; Kunes, Evan
1990-01-01
Recent developments concerning the performance and reliability of a spaceworthy adiabatic demagnetization refrigerator (ADR) for the AXAF X-ray spectrometer are considered. They include a procedure for growing the salt pill around a harness made up of 6080 gold-plated copper wires, a totally modular gas gap heat switch, and a suspension system utilizing Kevlar fibers.
NASA Astrophysics Data System (ADS)
Worek, W. M.; Zengh, W.; San, J.-Y.
1991-09-01
In order to perform exergy analyses to optimize the transient heat and mass transfer processes involving sorption by solid adsorbents, the thermodynamic properties of adsorbed water must be determined. In this paper, the integral enthalpy and entropy are determined directly from isotherm data of water adsorbed on silica gel particles and silica gel manufactured in the form of a felt with 25 percent cotton as a support and Teflon as a binder. These results are then used to evaluate the exergy losses, due to the sorption and the convective heat and mass transfer processes, that occur in each portion of an adiabatic desiccant dehumidificaton cycle.
Development of Adiabatic Demagnetization Refrigerator for X-ray mirocalorimeter experiments
NASA Astrophysics Data System (ADS)
Sato, Kosuke; Wada, Akane; Yatsu, Takahiro; Fujimoto, Ryuichi; Murakami, Toshio; Shinozaki, Keisuke
2009-12-01
For operating X-ray microcalorimeters, cryogenic temperature of 50-100 mK is required. For space applications, an adiabatic demagnetization refrigerator (ADR) is currently the only practical solution. At Kanazawa University, we are developing an ADR to operate X-ray microcalorimeters. So far, we made a salt pill of ˜67 g FAA (ferric ammonium alum) in house. The crystal was grown in a glass-epoxy resin case, and it was sealed with epoxy adhesive, to simplify the fabrication process. The salt pill as well as a superconducting magnet (3 T/9 A) and a mechanical heat-switch were mounted on a dedicated cryostat for this experiment, and cooling tests were performed with He bath temperature of 4.6 K and ˜3 K. The top of the salt pill reached about 200 mK and 140 mK, respectively. On the other hand, the bottom of the pill stayed at 0.7-1.0 K, suggesting the existence of an unexpected heat input.
Diestler, D J
2012-03-22
The Born-Oppenheimer (BO) description of electronically adiabatic molecular processes predicts a vanishing electronic flux density (j(e)),
Adiabatic topological quantum computing
NASA Astrophysics Data System (ADS)
Cesare, Chris; Landahl, Andrew J.; Bacon, Dave; Flammia, Steven T.; Neels, Alice
2015-07-01
Topological quantum computing promises error-resistant quantum computation without active error correction. However, there is a worry that during the process of executing quantum gates by braiding anyons around each other, extra anyonic excitations will be created that will disorder the encoded quantum information. Here, we explore this question in detail by studying adiabatic code deformations on Hamiltonians based on topological codes, notably Kitaev's surface codes and the more recently discovered color codes. We develop protocols that enable universal quantum computing by adiabatic evolution in a way that keeps the energy gap of the system constant with respect to the computation size and introduces only simple local Hamiltonian interactions. This allows one to perform holonomic quantum computing with these topological quantum computing systems. The tools we develop allow one to go beyond numerical simulations and understand these processes analytically.
Influence of Temperature and Pressure Change on Adiabatic and Isothermal Methanation Processes
NASA Astrophysics Data System (ADS)
Porubova, Jekaterina; Klemm, Marco; Kiendl, Isabel; Valters, Karlis; Markova, Darja; Repele, Mara; Bazbauers, Gatis
2012-09-01
Energy plans of many countries anticipate an increased use of biomethane for energy supply, i.e., in power and heat production as well as in the transport sector. Existing infrastructure of natural gas storage, supply and application provides a good platform to facilitate transfer to biomethane utilization on a larger scale. One key element of the biomethane system is the upgrade of the biomass-derived synthesis gas originating from different sources, to a quality of natural gas (SNG - Synthesis Natural Gas) via the methanation process for further injection into the natural gas grid.. The maximisation of efficiency of the methanation process is of critical importance in order to make biomethane technology viable for wider application. The aim of the study was to improve efficiency of the methanation process by finding the optimum temperatures and pressure. Theoretical modelling of adiabatic and isothermal methanation processes by using thermodynamic equilibrium calculations was introduced as a method for the study. The results show the impact of temperature and pressure changes on the overall efficiency of methane production. It can be concluded from the study that knowledge about the relation between temperature, pressure and the efficiency of the methanation process makes it possible to optimize the process under various biomass synthesized gas input conditions.
Coherent tunneling by adiabatic process in a four-waveguide optical coupler
NASA Astrophysics Data System (ADS)
Shi, Jian; Ma, Rui-Qiong; Duan, Zuo-Liang; Liang, Meng; Zhang, Wen-wen; Dong, Jun
2016-07-01
We numerically simulate Schrödinger-like paraxial wave equation of a four-waveguide system. The coherent tunneling by adiabatic passage in a four-waveguide optical coupler is analyzed by borrowing the dressed state theory of coherent atom system. We discuss the optical coupling mechanism and coupling efficiency of light energy in both intuitive and counterintuitive tunneling schemes and analyze the threshold condition from adiabatic to non-adiabatic regimes in intuitive scheme. The results show that this coupler can be used as power splitter under certain conditions.
NASA Astrophysics Data System (ADS)
Regenauer-Lieb, Klaus; Yuen, David A.
2000-02-01
Necking of the lithosphere involves complex nonlinear thermal-mechanical feedback mechanisms in an elasto-viscoplastic plate. The mode of extension of such plates relies on the mechanical properties of the upper part of the mantle and on the nucleation of ductile faults within the lithosphere. Our numerical model addresses the key problem of controls of ductile failure of the strongest part in the lithosphere. It is found that a small heterogeneity within this strong part can nucleate quasi-adiabatic shear bands. These develop spasmodically with time as finite amplitude instabilities with increasing temporal and length scales. The largest shear zone takes about 100,000 years to propagate through the entire lithosphere and can lead to a thermal instability for an ambient mantle temperature larger than 900 K. In our numerical model, thermal runaway occurs when the plate is severed. The temperature rise of the thermal instability is a function of the creep law exponent n and can be quenched for a lower n and smaller activation energy. The model is applicable to the problem of onset of continental break-up and holds the key to ductile instabilities in the Earth's lithosphere. The changing hot surface temperature on Venus might also have precipitated lithospheric instabilities in the past.
Development of an Adiabatic Demagnetization Refrigerator for X-ray Microcalorimeter Operations
NASA Astrophysics Data System (ADS)
Fujimoto, Ryuichi; Sato, Kosuke; Wada, Akane; Yatsu, Takahiro; Hoshino, Akio; Murakami, Toshio; Shinozaki, Keisuke
2010-10-01
An X-ray microcalorimeter is a non-dispersive spectrometer that measures the energy of an incident X-ray photon as a temperature rise. Operated at <0.1 K, it achieves very high resolving power. We are developing X-ray microcalorimeters for future γ-ray burst observations, and are now setting up a compact adiabatic demagnetization refrigerator (ADR) for X-ray microcalorimeter operations. We fabricated a paramagnetic salt pill, and integrated it with a superconducting magnet and a heat-switch in a dedicated He cryostat. By applying a magnetic field of 2.6 T at the bath temperature of 1.8 K, it achieved 0.1 K. The attainable temperature and the hold time were, however, limited due to unexpected heat load. We also successfully measured a resistance-temperature characteristics of a superconducting transition edge.
Miller, William H.; Orel, Ann E.
1980-11-01
A classical interpretation of the Dirac-Van Vleck spin version of valence bond theory is used to obtain a classical model for electronic degrees of freedom within the valence bond framework. The approach is illustrated by deriving the explicit forms of the classical Hamiltonians, involving electronic and heavy particle degrees of freedom, for the H-H{sub 2}, F-H{sub 2} , and O-H{sub 2} systems. It is also shown how the initial conditions for both electronic and heavy particle degrees of freedom are chosen to carry out a classical trajectory simulation of collision processes. The attractive feature of this model is that it is as eaaily applicable to electronically non-adiabatic processes as it is to adiabatic ones.
Seiler, Ch.; Hogan, S. D.; Schmutz, H.; Agner, J. A.; Merkt, F.
2011-02-18
A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90 deg., decelerated to zero velocity in less than 25 {mu}s, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed.
Wireless adiabatic power transfer
Rangelov, A.A.; Suchowski, H.; Silberberg, Y.; Vitanov, N.V.
2011-03-15
Research Highlights: > Efficient and robust mid-range wireless energy transfer between two coils. > The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. > Wireless energy transfer is insensitive to any resonant constraints. > Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.
Semiclassical analysis of the electron-nuclear coupling in electronic non-adiabatic processes
NASA Astrophysics Data System (ADS)
Agostini, Federica; Min, Seung Kyu; Gross, E. K. U.
2015-10-01
In the context of the exact factorization of the electron-nuclear wave function, the coupling between electrons and nuclei beyond the adiabatic regime is encoded (i) in the time-dependent vector and scalar potentials and (ii) in the electron-nuclear coupling operator. The former appear in the Schroedinger-like equation that drives the evolution of the nuclear degrees of freedom, whereas the latter is responsible for inducing non-adiabatic effects in the electronic evolution equation. As we have devoted previous studies to the analysis of the vector and scalar potentials, in this paper we focus on the properties of the electron-nuclear coupling operator, with the aim of describing a numerical procedure to approximate it within a semiclassical treatment of the nuclear dynamics.
Adiabatically driven Brownian pumps.
Rozenbaum, Viktor M; Makhnovskii, Yurii A; Shapochkina, Irina V; Sheu, Sheh-Yi; Yang, Dah-Yen; Lin, Sheng Hsien
2013-07-01
We investigate a Brownian pump which, being powered by a flashing ratchet mechanism, produces net particle transport through a membrane. The extension of the Parrondo's approach developed for reversible Brownian motors [Parrondo, Phys. Rev. E 57, 7297 (1998)] to adiabatically driven pumps is given. We demonstrate that the pumping mechanism becomes especially efficient when the time variation of the potential occurs adiabatically fast or adiabatically slow, in perfect analogy with adiabatically driven Brownian motors which exhibit high efficiency [Rozenbaum et al., Phys. Rev. E 85, 041116 (2012)]. At the same time, the efficiency of the pumping mechanism is shown to be less than that of Brownian motors due to fluctuations of the number of particles in the membrane. PMID:23944411
Wilken, F.; Bauer, D.
2006-11-17
The ionization of a one-dimensional model helium atom in short laser pulses using time-dependent density-functional theory is investigated. We calculate ionization probabilities as a function of laser intensity by approximating the correlation function of the system adiabatically with an explicit dependence on the fractional number of bound electrons. For the correlation potential we take the derivative discontinuity at integer numbers of bound electrons explicitly into account. This approach reproduces ionization probabilities from the solution of the time-dependent Schroedinger equation, in particular, the so-called knee due to nonsequential ionization.
Seiler, Ch; Hogan, S D; Schmutz, H; Agner, J A; Merkt, F
2011-02-18
A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90°, decelerated to zero velocity in less than 25 μs, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed. PMID:21405512
NASA Astrophysics Data System (ADS)
Landahl, Andrew
2012-10-01
Quantum computers promise to exploit counterintuitive quantum physics principles like superposition, entanglement, and uncertainty to solve problems using fundamentally fewer steps than any conventional computer ever could. The mere possibility of such a device has sharpened our understanding of quantum coherent information, just as lasers did for our understanding of coherent light. The chief obstacle to developing quantum computer technology is decoherence--one of the fastest phenomena in all of physics. In principle, decoherence can be overcome by using clever entangled redundancies in a process called fault-tolerant quantum error correction. However, the quality and scale of technology required to realize this solution appears distant. An exciting alternative is a proposal called ``adiabatic'' quantum computing (AQC), in which adiabatic quantum physics keeps the computer in its lowest-energy configuration throughout its operation, rendering it immune to many decoherence sources. The Adiabatic Quantum Architectures In Ultracold Systems (AQUARIUS) Grand Challenge Project at Sandia seeks to demonstrate this robustness in the laboratory and point a path forward for future hardware development. We are building devices in AQUARIUS that realize the AQC architecture on up to three quantum bits (``qubits'') in two platforms: Cs atoms laser-cooled to below 5 microkelvin and Si quantum dots cryo-cooled to below 100 millikelvin. We are also expanding theoretical frontiers by developing methods for scalable universal AQC in these platforms. We have successfully demonstrated operational qubits in both platforms and have even run modest one-qubit calculations using our Cs device. In the course of reaching our primary proof-of-principle demonstrations, we have developed multiple spinoff technologies including nanofabricated diffractive optical elements that define optical-tweezer trap arrays and atomic-scale Si lithography commensurate with placing individual donor atoms with
NASA Astrophysics Data System (ADS)
Peng, Y.; Lohmann, U.; Leaitch, R. W.
2003-12-01
Eleven profiles through liquid water cloud obtained during RACE (Radiation, Aerosol and Cloud Experiment) and NARE (North Atlantic Regional Experiment) are used to study the sensitivity of cloud droplet nucleation to the vertical gust velocity. Selected cloud microphysical data, size-distributed aerosol properties and particle chemistry are applied in an adiabatic parcel model to predict the activated cloud droplet number concentrations (N) using the frequency distribution of the measured in-cloud vertical velocities and again using a vertical velocity characteristic of observations. The simulated adiabatic value of N obtained using the standard deviation of the vertical velocity distribution agrees with the observed maximum N (the cloud droplet number in an adiabetic core) to within 5%. If the parameterization derived by Lin et al. [1997] is applied to obtain the cloud-average N from the maximum N, the average N agrees with the observed cloud-average N to within 20%. The simulated N obtained using the full probability density function of the vertical gust velocities is one approach that has been used to represent the cloud average N. This is based on the assumption that the average N is controlled by all variations in the updraft and not by the mixing process [Leaitch et al. 1996]. The value of N obtained in this manner is found to be higher than the observed average N by a factor of two. We believe that this result is because low vertical velocities do not contribute effectively to the cloud droplet nucleation. If we neglect the lowest 45% of all vertical velocities, then the difference between the simulated average N and the observed mean N is reduced to within 13%. These results suggest that it is appropriate to use a characteristic vertical velocity to predict the cloud droplet number concentration in climate models as done by Lohmann et al. [1999], where the subgrid variation of vertical velocity is diagnosed from the turbulent kinetic energy. The frequency
Adiabatic cooling of antiprotons.
Gabrielse, G; Kolthammer, W S; McConnell, R; Richerme, P; Kalra, R; Novitski, E; Grzonka, D; Oelert, W; Sefzick, T; Zielinski, M; Fitzakerley, D; George, M C; Hessels, E A; Storry, C H; Weel, M; Müllers, A; Walz, J
2011-02-18
Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3×10(6) p are cooled to 3.5 K-10(3) times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e(-) (with many fewer e(-) than p in preparation for adiabatic cooling. No p are lost during either process-a significant advantage for rare particles. PMID:21405511
Adiabatic Cooling of Antiprotons
Gabrielse, G.; Kolthammer, W. S.; McConnell, R.; Richerme, P.; Kalra, R.; Novitski, E.; Oelert, W.; Grzonka, D.; Sefzick, T.; Zielinski, M.; Fitzakerley, D.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Muellers, A.; Walz, J.
2011-02-18
Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3x10{sup 6} p are cooled to 3.5 K--10{sup 3} times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e{sup -} (with many fewer e{sup -} than p) in preparation for adiabatic cooling. No p are lost during either process--a significant advantage for rare particles.
Adiabatically implementing quantum gates
Sun, Jie; Lu, Songfeng Liu, Fang
2014-06-14
We show that, through the approach of quantum adiabatic evolution, all of the usual quantum gates can be implemented efficiently, yielding running time of order O(1). This may be considered as a useful alternative to the standard quantum computing approach, which involves quantum gates transforming quantum states during the computing process.
Geometry of the Adiabatic Theorem
ERIC Educational Resources Information Center
Lobo, Augusto Cesar; Ribeiro, Rafael Antunes; Ribeiro, Clyffe de Assis; Dieguez, Pedro Ruas
2012-01-01
We present a simple and pedagogical derivation of the quantum adiabatic theorem for two-level systems (a single qubit) based on geometrical structures of quantum mechanics developed by Anandan and Aharonov, among others. We have chosen to use only the minimum geometric structure needed for the understanding of the adiabatic theorem for this case.…
NASA Astrophysics Data System (ADS)
Peña Angulo, Dhais; Trigo, Ricardo; Cortesi, Nicola; Gonzalez-Hidalgo, Jose Carlos
2016-04-01
We have analyzed at monthly scale the spatial distribution of Pearson correlation between monthly mean of maximum (Tmax) and minimum (Tmin) temperatures with weather types (WTs) in the Iberian Peninsula (IP), represent them in a high spatial resolution grid (10km x 10km) from MOTEDAS dataset (Gonzalez-Hidalgo et al., 2015a). The WT classification was that developed by Jenkinson and Collison, adapted to the Iberian Peninsula by Trigo and DaCamara, using Sea Level Pressure data from NCAR/NCEP Reanalysis dataset (period 1951-2010). The spatial distribution of Pearson correlations shows a clear zonal gradient in Tmax under the zonal advection produced in westerly (W) and easterly (E) flows, with negative correlation in the coastland where the air mass come from but positive correlation to the inland areas. The same is true under North-West (NW), North-East (NE), South-West (SW) and South-East (SE) WTs. These spatial gradients are coherent with the spatial distribution of the main mountain chain and offer an example of regional adiabatic phenomena that affect the entire IP (Peña-Angulo et al., 2015b). These spatial gradients have not been observed in Tmin. We suggest that Tmin values are less sensitive to changes in Sea Level Pressure and more related to local factors. These directional WT present a monthly frequency over 10 days and could be a valuable tool for downscaling processes. González-Hidalgo J.C., Peña-Angulo D., Brunetti M., Cortesi, C. (2015a): MOTEDAS: a new monthly temperature database for mainland Spain and the trend in temperature (1951-2010). International Journal of Climatology 31, 715-731. DOI: 10.1002/joc.4298 Peña-Angulo, D., Trigo, R., Cortesi, C., González-Hidalgo, J.C. (2015b): The influence of weather types on the monthly average maximum and minimum temperatures in the Iberian Peninsula. Submitted to Hydrology and Earth System Sciences.
Dephasing effects on stimulated Raman adiabatic passage in tripod configurations
Lazarou, C.; Vitanov, N. V.
2010-09-15
We present an analytic description of the effects of dephasing processes on stimulated Raman adiabatic passage in a tripod quantum system. To this end, we develop an effective two-level model. Our analysis makes use of the adiabatic approximation in the weak dephasing regime. An effective master equation for a two-level system formed by two dark states is derived, where analytic solutions are obtained by utilizing the Demkov-Kunike model. From these, it is found that the fidelity for the final coherent superposition state decreases exponentially for increasing dephasing rates. Depending on the pulse ordering and for adiabatic evolution, the pulse delay can have an inverse effect.
ERIC Educational Resources Information Center
Gonen, S.
2014-01-01
The present study was carried out with 46 teacher candidates taking the course of "Thermodynamics" in the Department of Physics Teaching. The purpose of the study was to determine the difficulties that teacher candidates experienced in explaining the heat, work and internal energy relationships in the processes of adiabatic compression…
NASA Astrophysics Data System (ADS)
Song, Xinfang; Wang, Wenyuan; Fu, Libin
2016-04-01
Oscillating electric field is chosen to investigate the electron-positron pair production process by using a quantum kinetic theory and the effective mass model [Phys. Rev. Lett. 112, 050402 (2014)]. The particle yield exhibits a characteristic oscillatory structure which is related to the multi-photon thresholds. The true peak positions are typically slightly above the naive threshold estimate, which is defined as frequency shift. During the numerical calculations, we find the frequency shift can be affected by the system parameters under adiabatic closing the external field, it is worthwhile to study in detail. In this paper, we investigate the frequency shift and the sub-band effect in electron-positron pair production with oscillating electric field. First, a quantum kinetic theory and the effective mass are presented to obtain the frequency shift, the results are fitted very well. And we find the frequency shift and the sub-band effect can be influenced by pulse duration, photon number, and strength of the external field. The frequency shift becomes evident as increases of photon number and the external field strength. The sub-band width is relatively lower at longer pulse duration, higher photon number region, and weaker external field. The results shown in the paper are helpful for understanding multi-photon pair production process in the strong field.
NASA Astrophysics Data System (ADS)
Song, Xinfang; Wang, Wenyuan; Fu, Libin
2016-09-01
Oscillating electric field is chosen to investigate the electron-positron pair production process by using a quantum kinetic theory and the effective mass model [Phys. Rev. Lett. 112, 050402 (2014)]. The particle yield exhibits a characteristic oscillatory structure which is related to the multi-photon thresholds. The true peak positions are typically slightly above the naive threshold estimate, which is defined as frequency shift. During the numerical calculations, we find the frequency shift can be affected by the system parameters under adiabatic closing the external field, it is worthwhile to study in detail. In this paper, we investigate the frequency shift and the sub-band effect in electron-positron pair production with oscillating electric field. First, a quantum kinetic theory and the effective mass are presented to obtain the frequency shift, the results are fitted very well. And we find the frequency shift and the sub-band effect can be influenced by pulse duration, photon number, and strength of the external field. The frequency shift becomes evident as increases of photon number and the external field strength. The sub-band width is relatively lower at longer pulse duration, higher photon number region, and weaker external field. The results shown in the paper are helpful for understanding multi-photon pair production process in the strong field.
Kappa Distribution in a Homogeneous Medium: Adiabatic Limit of a Super-diffusive Process?
NASA Astrophysics Data System (ADS)
Roth, I.
2015-12-01
The classical statistical theory predicts that an ergodic, weakly interacting system like charged particles in the presence of electromagnetic fields, performing Brownian motions (characterized by small range deviations in phase space and short-term microscopic memory), converges into the Gibbs-Boltzmann statistics. Observation of distributions with a kappa-power-law tails in homogeneous systems contradicts this prediction and necessitates a renewed analysis of the basic axioms of the diffusion process: characteristics of the transition probability density function (pdf) for a single interaction, with a possibility of non-Markovian process and non-local interaction. The non-local, Levy walk deviation is related to the non-extensive statistical framework. Particles bouncing along (solar) magnetic field with evolving pitch angles, phases and velocities, as they interact resonantly with waves, undergo energy changes at undetermined time intervals, satisfying these postulates. The dynamic evolution of a general continuous time random walk is determined by pdf of jumps and waiting times resulting in a fractional Fokker-Planck equation with non-integer derivatives whose solution is given by a Fox H-function. The resulting procedure involves the known, although not frequently used in physics fractional calculus, while the local, Markovian process recasts the evolution into the standard Fokker-Planck equation. Solution of the fractional Fokker-Planck equation with the help of Mellin transform and evaluation of its residues at the poles of its Gamma functions results in a slowly converging sum with power laws. It is suggested that these tails form the Kappa function. Gradual vs impulsive solar electron distributions serve as prototypes of this description.
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NASA Astrophysics Data System (ADS)
Krix, David; Nienhaus, Hermann
2014-08-01
Thin potassium films grown on Si(001) substrates are used to measure internal chemicurrents and the external emission of exoelectrons simultaneously during adsorption of molecular oxygen on K surfaces at 120 K. The experiments clarify the dynamics of electronic excitations at a simple metal with a narrow valence band. X-ray photoemission reveals that for exposures below 5 L almost exclusively peroxide K2O2 is formed, i.e., no dissociation of the molecule occurs during interaction. Still a significant chemicurrent and a delayed exoelectron emission are detected due to a rapid injection of unoccupied molecular levels below the Fermi level. Since the valence band width of potassium is approximately equal to the potassium work function (2.4 eV) the underlying mechanism of exoemission is an Auger relaxation whereas chemicurrents are detected after resonant charge transfer from the metal valence band into the injected level. The change of the chemicurrent and exoemission efficiencies with oxygen coverage can be deduced from the kinetics of the reaction and the recorded internal and external emission currents traces. It is shown that the non-adiabaticity of the reaction increases with coverage due to a reduction of the electronic density of states at the surface while the work function does not vary significantly. Therefore, the peroxide formation is one of the first reaction systems which exhibits varying non-adiabaticity and efficiencies during the reaction. Non-adiabatic calculations based on model Hamiltonians and density functional theory support the picture of chemicurrent generation and explain the rapid injection of hot hole states by an intramolecular motion, i.e., the expansion of the oxygen molecule on the timescale of a quarter of a vibrational period.
Krix, David; Nienhaus, Hermann
2014-08-21
Thin potassium films grown on Si(001) substrates are used to measure internal chemicurrents and the external emission of exoelectrons simultaneously during adsorption of molecular oxygen on K surfaces at 120 K. The experiments clarify the dynamics of electronic excitations at a simple metal with a narrow valence band. X-ray photoemission reveals that for exposures below 5 L almost exclusively peroxide K2O2 is formed, i.e., no dissociation of the molecule occurs during interaction. Still a significant chemicurrent and a delayed exoelectron emission are detected due to a rapid injection of unoccupied molecular levels below the Fermi level. Since the valence band width of potassium is approximately equal to the potassium work function (2.4 eV) the underlying mechanism of exoemission is an Auger relaxation whereas chemicurrents are detected after resonant charge transfer from the metal valence band into the injected level. The change of the chemicurrent and exoemission efficiencies with oxygen coverage can be deduced from the kinetics of the reaction and the recorded internal and external emission currents traces. It is shown that the non-adiabaticity of the reaction increases with coverage due to a reduction of the electronic density of states at the surface while the work function does not vary significantly. Therefore, the peroxide formation is one of the first reaction systems which exhibits varying non-adiabaticity and efficiencies during the reaction. Non-adiabatic calculations based on model Hamiltonians and density functional theory support the picture of chemicurrent generation and explain the rapid injection of hot hole states by an intramolecular motion, i.e., the expansion of the oxygen molecule on the timescale of a quarter of a vibrational period. PMID:25149810
Krix, David; Nienhaus, Hermann
2014-08-21
Thin potassium films grown on Si(001) substrates are used to measure internal chemicurrents and the external emission of exoelectrons simultaneously during adsorption of molecular oxygen on K surfaces at 120 K. The experiments clarify the dynamics of electronic excitations at a simple metal with a narrow valence band. X-ray photoemission reveals that for exposures below 5 L almost exclusively peroxide K{sub 2}O{sub 2} is formed, i.e., no dissociation of the molecule occurs during interaction. Still a significant chemicurrent and a delayed exoelectron emission are detected due to a rapid injection of unoccupied molecular levels below the Fermi level. Since the valence band width of potassium is approximately equal to the potassium work function (2.4 eV) the underlying mechanism of exoemission is an Auger relaxation whereas chemicurrents are detected after resonant charge transfer from the metal valence band into the injected level. The change of the chemicurrent and exoemission efficiencies with oxygen coverage can be deduced from the kinetics of the reaction and the recorded internal and external emission currents traces. It is shown that the non-adiabaticity of the reaction increases with coverage due to a reduction of the electronic density of states at the surface while the work function does not vary significantly. Therefore, the peroxide formation is one of the first reaction systems which exhibits varying non-adiabaticity and efficiencies during the reaction. Non-adiabatic calculations based on model Hamiltonians and density functional theory support the picture of chemicurrent generation and explain the rapid injection of hot hole states by an intramolecular motion, i.e., the expansion of the oxygen molecule on the timescale of a quarter of a vibrational period.
Cotton, Stephen J.; Miller, William H.
2013-12-21
A recently described symmetrical windowing methodology [S. J. Cotton and W. H. Miller, J. Phys. Chem. A 117, 7190 (2013)] for quasi-classical trajectory simulations is applied here to the Meyer-Miller [H.-D. Meyer and W. H. Miller, J. Chem. Phys. 70, 3214 (1979)] model for the electronic degrees of freedom in electronically non-adiabatic dynamics. Results generated using this classical approach are observed to be in very good agreement with accurate quantum mechanical results for a variety of test applications, including problems where coherence effects are significant such as the challenging asymmetric spin-boson system.
NASA Astrophysics Data System (ADS)
Ahmed, Hilal; Khan, Shakeel; Khan, Wasi; Nongjai, Razia; Khan, Imran
2014-11-01
We have systematically investigated structural, electrical and magnetic properties of Fe doped La0.33Sr0.67MnO3 manganites synthesized through solid-state reaction-route. All the samples are found to have rhombohedral crystal structure. The crystallite sizes obtained by XRD data are much smaller than the average grain size obtained by scanning electron microscope (SEM). Temperature dependent resistivity data were fitted using Mott's variable-range hopping (VRH) and small polaron hopping (SPH) models for obtaining different parameters. The adiabatic SPH conduction mechanism is followed almost for both samples in the absence of magnetic field but a switching from adiabatic to non-adiabatic SPH conduction mechanism is found in the presence of magnetic field. Temperature dependent magnetization (M-T) measurements confirm the decrease in Curie-temperature (TC) with Fe doping. Both the samples exhibited ferromagnetic behavior at 10 K and 300 K with a small hysteresis loop and low coercivity.
NASA Astrophysics Data System (ADS)
Ahmed, M. G.; Hermier, Y.
2013-09-01
The National Institute for Standards (NIS), in cooperation with the French National Metrology Institute (LNE-CNAM), has recently developed a new adiabatic calorimeter, to realize the International Temperature Scale of 1990 (ITS-90) in the temperature range between 54 K and 273 K using Capsule Standard Platinum Resistance Thermometers (CSPRTs). The work has been realized through an international scientific-cooperation project "IMHOTEP" between the two sides. The new calorimeter comprises a cylindrical double-wall vacuum-tight stainless steel Dewar that withstands evacuation on the liquid nitrogen to reach a temperature close to the oxygen triple point. The thermal shield accommodates a multi-compartment cell containing the oxygen and argon triple-points cells. The temperature control for best adiabatic conditions is achieved through PID software, running under LABVIEW environment. Two calorimeters have been constructed. The first one was installed at LNE-CNAM and tested for optimum adiabatic conditions. The system was then transferred to NIS. The second calorimeter was tested and stayed at LNE-CNAM. Experiments, at NIS, showed the possibility of reaching a temperature close to the oxygen triple point. Uncertainties for CSPRTs calibrations were 0.27 and 0.25 mK for triple points of oxygen and argon respectively.
Scaleup of IGT MILDGAS Process to a process development unit
Campbell, J.A.L.; Longanbach, J.; Johnson, R.; Underwood, K.; Mead, J.; Carty, R.H.
1992-12-31
The MILDGAS process is capable of processing both eastern caking and western non-caking coals to yield a slate of liquid and solid products. The liquids can be processed to produce: feedstocks for chemicals; pitch for use as a binder for electrodes in the aluminum industry; and fuels. Depending on the feed coal characteristics and the operating conditions, the char can be used as an improved fuel for power generation or can be used to make form coke for steel-making blast furnaces or for foundry cupola operations. The specific objectives of the program are to: design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for design scaleup; obtain large batches of coal-derived co-products for industrial evaluation; prepare a detailed design of a demonstration unit; and develop technical and economic plans for commercialization of the MILDGAS process. In this paper, the authors present the process design of the PDU facility, a description of the expected product distribution and the project test plan to be implemented in the program.
Studies in Chaotic adiabatic dynamics
Jarzynski, C.
1994-01-01
Chaotic adiabatic dynamics refers to the study of systems exhibiting chaotic evolution under slowly time-dependent equations of motion. In this dissertation the author restricts his attention to Hamiltonian chaotic adiabatic systems. The results presented are organized around a central theme, namely, that the energies of such systems evolve diffusively. He begins with a general analysis, in which he motivates and derives a Fokker-Planck equation governing this process of energy diffusion. He applies this equation to study the {open_quotes}goodness{close_quotes} of an adiabatic invariant associated with chaotic motion. This formalism is then applied to two specific examples. The first is that of a gas of noninteracting point particles inside a hard container that deforms slowly with time. Both the two- and three-dimensional cases are considered. The results are discussed in the context of the Wall Formula for one-body dissipation in nuclear physics, and it is shown that such a gas approaches, asymptotically with time, an exponential velocity distribution. The second example involves the Fermi mechanism for the acceleration of cosmic rays. Explicit evolution equations are obtained for the distribution of cosmic ray energies within this model, and the steady-state energy distribution that arises when this equation is modified to account for the injection and removal of cosmic rays is discussed. Finally, the author re-examines the multiple-time-scale approach as applied to the study of phase space evolution under a chaotic adiabatic Hamiltonian. This leads to a more rigorous derivation of the above-mentioned Fokker-Planck equation, and also to a new term which has relevance to the problem of chaotic adiabatic reaction forces (the forces acting on slow, heavy degrees of freedom due to their coupling to light, fast chaotic degrees).
Adiabatic Compression of Oxygen: Real Fluid Temperatures
NASA Technical Reports Server (NTRS)
Barragan, Michelle; Wilson, D. Bruce; Stoltzfus, Joel M.
2000-01-01
The adiabatic compression of oxygen has been identified as an ignition source for systems operating in enriched oxygen atmospheres. Current practice is to evaluate the temperature rise on compression by treating oxygen as an ideal gas with constant heat capacity. This paper establishes the appropriate thermodynamic analysis for the common occurrence of adiabatic compression of oxygen and in the process defines a satisfactory equation of state (EOS) for oxygen. It uses that EOS to model adiabatic compression as isentropic compression and calculates final temperatures for this system using current approaches for comparison.
Laser forming process development
Blake, R.J.
1996-12-31
This paper is a summary of the activities performed for the process development of laser thermal forming sheet metal parts in support of rapid prototyping. A 400 watt pulsed Nd:YAG laser and 50 watt desktop CO{sub 2} laser were used during initial process development. Several tool-assisted laser forming approaches were conceived during the development of the process, and simple fixtures for process development/understanding were used throughout all testing. Much of the actual forming was performed with the base material in an unfixtured state. CRES (304) was used for baseline development, but the effort was directed toward forming titanium (e.g., 6Al-4V, 15V-3Cr-3Sn-3Al). Several DOE (i.e., Design of Experiment) techniques were employed during development and a Neural Net Computer Model was conceived for process control. This program was a joint effort in cooperation with the American Welding Society under contract with the Defense Advanced Research Projects Agency (DARPA). A synopsis of the laser forming process development, future opportunities, and applications are presented.
NASA Astrophysics Data System (ADS)
Wehrenberg, Christopher; Prisbrey, Shon T.; Park, Hye-Sook; Benedetti, L. Robin; Huntington, Channing; McNaney, James; Smith, Ray; Panas, Cynthia; Cook, Angela; Remington, Bruce; Arsenlis, Tom; Graham, Peter
2015-11-01
A series of experiments were performed on NIF to develop a planar, 3-shock, low-adiabat drive for material science experiments. Physics samples (Ta, Pb, etc.) are loaded to 3-4 Mbar while staying well below the melt temperature. X-ray ablation from an indirect drive launches a strong (~ 50 Mbar), decaying shock through a precision fabricated ``reservoir,'' consisting of a CH ablator, followed by layers of Al, CH(18.75%I), ~ 375 mg/cc carbonized resorcinol formaldehyde foam, and a final layer of low density (10-35) mg/cc foam. As the releasing reservoir stagnates on a Ta drive plate, VISAR is used to measures the resulting compression waves. The lowest density reservoir layer is responsible for the leading shock and induces the most entropy during the drive. LLNL has developed a new, low-density foam called JX6 (C20H30) for the purpose of controlling the leading shock. We will describe a series of experiments done on NIF to test the combined release and recompression properties of JX6 and to develop a new, lower-adiabat drive. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.
Robust adiabatic sum frequency conversion.
Suchowski, Haim; Prabhudesai, Vaibhav; Oron, Dan; Arie, Ady; Silberberg, Yaron
2009-07-20
We discuss theoretically and demonstrate experimentally the robustness of the adiabatic sum frequency conversion method. This technique, borrowed from an analogous scheme of robust population transfer in atomic physics and nuclear magnetic resonance, enables the achievement of nearly full frequency conversion in a sum frequency generation process for a bandwidth up to two orders of magnitude wider than in conventional conversion schemes. We show that this scheme is robust to variations in the parameters of both the nonlinear crystal and of the incoming light. These include the crystal temperature, the frequency of the incoming field, the pump intensity, the crystal length and the angle of incidence. Also, we show that this extremely broad bandwidth can be tuned to higher or lower central wavelengths by changing either the pump frequency or the crystal temperature. The detailed study of the properties of this converter is done using the Landau-Zener theory dealing with the adiabatic transitions in two level systems. PMID:19654679
Bond selective chemistry beyond the adiabatic approximation
Butler, L.J.
1993-12-01
One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.
Experimental demonstration of composite adiabatic passage
NASA Astrophysics Data System (ADS)
Schraft, Daniel; Halfmann, Thomas; Genov, Genko T.; Vitanov, Nikolay V.
2013-12-01
We report an experimental demonstration of composite adiabatic passage (CAP) for robust and efficient manipulation of two-level systems. The technique represents a altered version of rapid adiabatic passage (RAP), driven by composite sequences of radiation pulses with appropriately chosen phases. We implement CAP with radio-frequency pulses to invert (i.e., to rephase) optically prepared spin coherences in a Pr3+:Y2SiO5 crystal. We perform systematic investigations of the efficiency of CAP and compare the results with conventional π pulses and RAP. The data clearly demonstrate the superior features of CAP with regard to robustness and efficiency, even under conditions of weakly fulfilled adiabaticity. The experimental demonstration of composite sequences to support adiabatic passage is of significant relevance whenever a high efficiency or robustness of coherent excitation processes need to be maintained, e.g., as required in quantum information technology.
Development of metallization process
NASA Technical Reports Server (NTRS)
Garcia, A., III
1983-01-01
A non lead frit paste is evaluated. A two step process is discussed where the bulk of the metallization is Mo/Sn but a small ohmic pad is silver. A new matrix of paste formulations is developed. A variety of tests are performed on paste samples to determine electrical, thermal and structural properties.
Ghosh, S.; Mensinger, M.C.; Sajjad, A.; Henry, M.P.
1984-01-01
The overall objective of the program is to demonstrate and commercialize the IGT two-phase BIOGAS Process for optimized methane production from, and simultaneous stabilization of, municipal solid waste (MSW). The specific objective of the current program is to conduct a laboratory-scale investigation of simple, cost-effective feed pretreatment techniques and selected digestion reactor designs to optimize methane production from MSW-sludge blends, and to select the best pretreatment and digestion conditions for testing during the subsequent program for process development unit (PDU) operation. A significant portion of the program efforts to date has been directed at evaluating and/or developing feeding, mixing and discharging systems for handling high concentration, large particle size RDF slurries for anaerobic digestion processes. The performance of such processes depends significantly on the operational success of these subsystems. The results of the subsystem testing have been implemented in the design and operation of the 10-L, 20-L, and 125-L digesters. These results will also be utilized to design the CSTR and the upflow digesters of a large two-phase system. Data collected during the initial phase of this research showed in general that methane production from RDF decreased as the loading rate was increased. Thermophilic digestion did not appear to be significantly better than mesophlic digestion. 9 figures, 3 tables.
Geometrical representation of sum frequency generation and adiabatic frequency conversion
NASA Astrophysics Data System (ADS)
Suchowski, Haim; Oron, Dan; Arie, Ady; Silberberg, Yaron
2008-12-01
We present a geometrical representation of the process of sum frequency generation in the undepleted pump approximation, in analogy with the known optical Bloch equations. We use this analogy to propose a technique for achieving both high efficiency and large bandwidth in sum frequency conversion using the adiabatic inversion scheme. The process is analogous with rapid adiabatic passage in NMR, and adiabatic constraints are derived in this context. This adiabatic frequency conversion scheme is realized experimentally using an aperiodically poled potassium titanyl phosphate (KTP) device, where we achieved high efficiency signal-to-idler conversion over a bandwidth of 140nm .
Entanglement and adiabatic quantum computation
NASA Astrophysics Data System (ADS)
Ahrensmeier, D.
2006-06-01
Adiabatic quantum computation provides an alternative approach to quantum computation using a time-dependent Hamiltonian. The time evolution of entanglement during the adiabatic quantum search algorithm is studied, and its relevance as a resource is discussed.
Cotton, Stephen J; Miller, William H
2015-12-17
A recent series of papers has shown that a symmetrical quasi-classical (SQC) windowing procedure applied to the Meyer-Miller (MM) classical vibronic Hamiltonian provides a very good treatment of electronically nonadiabatic processes in a variety of benchmark model systems, including systems that exhibit strong quantum coherence effects and some which other approximate approaches have difficulty in describing correctly. In this paper, a different classical electronic Hamiltonian for the treatment of electronically nonadiabatic processes is proposed (and "quantized" via the SQC windowing approach), which maps the dynamics of F coupled electronic states to a set of F spin-(1)/2 degrees of freedom (DOF), similar to the Fermionic spin model described by Miller and White (J. Chem. Phys. 1986, 84, 5059). It is noted that this spin-mapping (SM) Hamiltonian is an exact Hamiltonian if treated as a quantum mechanical (QM) operator-and thus QM'ly equivalent to the MM Hamiltonian-but that an analytically distinct classical analogue is obtained by replacing the QM spin-operators with their classical counterparts. Due to their analytic differences, a practical comparison is then made between the MM and SM Hamiltonians (when quantized with the SQC technique) by applying the latter to many of the same benchmark test problems successfully treated in our recent work with the SQC/MM model. We find that for every benchmark problem the MM model provides (slightly) better agreement with the correct quantum nonadiabatic transition probabilities than does the new SM model. This is despite the fact that one might expect, a priori, a more natural description of electronic state populations (occupied versus unoccupied) to be provided by DOF with only two states, i.e., spin-(1)/2 DOF, rather than by harmonic oscillator DOF which have an infinite manifold of states (though only two of these are ever occupied). PMID:26299361
NASA Technical Reports Server (NTRS)
Richards, Paul L.
2005-01-01
Mechanical heat switches are used in conjunction with sorption refrigerators, adiabatic demagnetization refrigerators and for other cryogenic tasks including the pre-cooling cryogenic systems. They use a mechanical actuator which closes Au plated Cu jaws on an Au plated Cu bar. The thermal conductance in the closed position is essentially independent of the area of the jaws and proportional to the force applied. It varies linearly with T. It is approximately 10mW/K for 200 N at 1.5K. In some applications, the heat switch can be driven from outside the cryostat by a rotating rod and a screw. Such heat switches are available commercially from several sources. In other applications, including systems for space, it is desirable to drive the switch using a cold linear motor, or solenoid. Superconducting windings are used at temperatures s 4.2K to minimize power dissipation, but are not appropriate for pre-cooling a system at higher temperatures. This project was intended to improve the design of solenoid activated mechanical heat switches and to provide such switches as required to support the development of Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10 K to 50 mK at GSFC. By the time funding began in 5/1/01, the immediate need for mechanical heat switches at GSFC had subsided but, at the same time, the opportunity had arisen to improve the design of mechanical heat switching by incorporating a "latching solenoid". In this device, the solenoid current is required only for changing the state of the switch and not during the whole time that the switch is closed.
The study of adiabatic shear band instability in a pearlitic 4340 steel using a dynamic punch test
Zurek, A.K. )
1994-11-01
At low strain rates and moderate levels of strain, slip and twinning are the most common deformation mechanisms in metals and alloys. Both mechanisms are highly correlated with the crystallography of the material. At higher strain rates and levels of strain, deformation instabilities, such as adiabatic shear bands (ASB), may develop. These bands are planar in nature, and their formation is related more to the specimen geometry, deformation process, and mechanical properties of a material than to its local crystallography. The formation of adiabatic shear band instabilities in a pearlitic 4340 steel using a dynamic punch test has been studied. The dynamic punch-impact test produced white-etching adiabatic shear bands. The average strain of 0.5 was sufficient to produce adiabatic shear bands in this steel at an average strain rate of 18,000 s[sup [minus]1]. Nanohardness variations found across the adiabatic shear at an average strain rate of 18,000 s[sup [minus]1]. Nanohardness variations found across the adiabatic shear band are thought to be caused by the fragmentation and spheriodization of the Fe[sub 3]C and the overall deformation and work hardening of the pearlitic microstructure. The cracks formed at the termination of the adiabatic shear band caused the sample to fracture in a ductile mode.
Effect of Strain on Microstructure Evolution of 1Cr18Ni9Ti Stainless Steel During Adiabatic Shearing
NASA Astrophysics Data System (ADS)
Yang, Y.; Jiang, L. H.; Luo, S. H.; Hu, H. B.; Tang, T. G.; Zhang, Q. M.
2016-01-01
Dynamic shear test was conducted on the hat-shaped specimen of the thermo-mechanical-processed 1Cr18Ni9Ti stainless steel by using the split Hopkinson pressure bar at ambient temperature. The effect of the shear strain on the microstructure evolution was investigated during adiabatic shearing. The results revealed that the development of adiabatic shear localization went through three stages, including the incubation period, the development stage, and the maturity period. TEM observations showed that the grains in the shear region were elongated, and the elongated grains were gradually evolved into equiaxed nano-grains of 100 nm as shear strain increased. The rotational dynamic recrystallization kinetics calculation showed that subgrains had sufficient time to generate an equiaxed microcrystalline structure by rotation within the deformation time. Based on the observation of the evolution of dislocations and sub-grains in the adiabatic shear region, a model of the microstructure evolution was established during the adiabatic shearing.
Graph isomorphism and adiabatic quantum computing
NASA Astrophysics Data System (ADS)
Gaitan, Frank; Clark, Lane
2014-02-01
In the graph isomorphism (GI) problem two N-vertex graphs G and G' are given and the task is to determine whether there exists a permutation of the vertices of G that preserves adjacency and transforms G →G'. If yes, then G and G' are said to be isomorphic; otherwise they are nonisomorphic. The GI problem is an important problem in computer science and is thought to be of comparable difficulty to integer factorization. In this paper we present a quantum algorithm that solves arbitrary instances of GI and which also provides an approach to determining all automorphisms of a given graph. We show how the GI problem can be converted to a combinatorial optimization problem that can be solved using adiabatic quantum evolution. We numerically simulate the algorithm's quantum dynamics and show that it correctly (i) distinguishes nonisomorphic graphs; (ii) recognizes isomorphic graphs and determines the permutation(s) that connect them; and (iii) finds the automorphism group of a given graph G. We then discuss the GI quantum algorithm's experimental implementation, and close by showing how it can be leveraged to give a quantum algorithm that solves arbitrary instances of the NP-complete subgraph isomorphism problem. The computational complexity of an adiabatic quantum algorithm is largely determined by the minimum energy gap Δ (N) separating the ground and first-excited states in the limit of large problem size N ≫1. Calculating Δ (N) in this limit is a fundamental open problem in adiabatic quantum computing, and so it is not possible to determine the computational complexity of adiabatic quantum algorithms in general, nor consequently, of the specific adiabatic quantum algorithms presented here. Adiabatic quantum computing has been shown to be equivalent to the circuit model of quantum computing, and so development of adiabatic quantum algorithms continues to be of great interest.
Symmetry-Protected Quantum Adiabatic Transistors
NASA Astrophysics Data System (ADS)
Williamson, Dominic J.; Bartlett, Stephen D.
2014-03-01
An essential development in the history of computing was the invention of the transistor as it allowed logic circuits to be implemented in a robust and modular way. The physical characteristics of semiconductor materials were the key to building these devices. We aim to present an analogous development for quantum computing by showing that quantum adiabatic transistors (as defined by Flammia et al.) are built upon the essential qualities of symmetry-protected (SP) quantum ordered phases in one dimension. Flammia et al. and Renes et al. have demonstrated schemes for universal adiabatic quantum computation using quantum adiabatic transistors described by interacting spin chain models with specifically chosen Hamiltonian terms. We show that these models can be understood as specific examples of the generic situation in which all SP phases lead to quantum computation on encoded edge degrees of freedom by adiabatically traversing a symmetric phase transition into a trivial symmetric phase. This point of view is advantageous as it allows us to readily see that the computational properties of a quantum adiabatic transistor arise from a phase of matter rather than due to carefully tuned interactions.
NASA Astrophysics Data System (ADS)
Lejosne, SolèNe; Boscher, Daniel; Maget, Vincent; Rolland, Guy
2012-08-01
In this paper, a new approach for the derivation of the instantaneous rate of change of the third adiabatic invariant is introduced. It is based on the tracking of the bounce-averaged motion of guiding centers with assumptions that are only kept to the necessary conditions for definition and conservation of the first two adiabatic invariants. The derivation is first given in the case of trapped equatorial particles drifting in a time varying magnetic field in the absence of electrostatic potential. It is then extended to more general cases including time varying electric potentials and non-equatorial particles. Finally, the general formulation of the third adiabatic invariant time derivative is related to the description of the radial diffusion process occurring in the radiation belts. It highlights the links that exist between previous theoretical works with the objective of a better understanding of the radial diffusion process. A theoretical validation in the specific case of equatorial particles drifting in a magnetic field model whose disturbed part is limited to the first terms of a spherical expansion is also presented.
Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo
White, Alexander J.; Gorshkov, Vyacheslav N.; Tretiak, Sergei; Mozyrsky, Dmitry
2015-07-07
Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficientmore » as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In many cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems.« less
Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo
White, Alexander J.; Gorshkov, Vyacheslav N.; Tretiak, Sergei; Mozyrsky, Dmitry
2015-07-07
Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficient as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In many cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems.
Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo
White, Alexander J.; Gorshkov, Vyacheslav N.; Tretiak, Sergei; Mozyrsky, Dmitry
2015-07-07
Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficient as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In most cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems.
Adiabatic approximation for the density matrix
NASA Astrophysics Data System (ADS)
Band, Yehuda B.
1992-05-01
An adiabatic approximation for the Liouville density-matrix equation which includes decay terms is developed. The adiabatic approximation employs the eigenvectors of the non-normal Liouville operator. The approximation is valid when there exists a complete set of eigenvectors of the non-normal Liouville operator (i.e., the eigenvectors span the density-matrix space), the time rate of change of the Liouville operator is small, and an auxiliary matrix is nonsingular. Numerical examples are presented involving efficient population transfer in a molecule by stimulated Raman scattering, with the intermediate level of the molecule decaying on a time scale that is fast compared with the pulse durations of the pump and Stokes fields. The adiabatic density-matrix approximation can be simply used to determine the density matrix for atomic or molecular systems interacting with cw electromagnetic fields when spontaneous emission or other decay mechanisms prevail.
Bazzani, A.; Turchetti, G.; Benedetti, C.; Rambaldi, S.; Servizi, G.
2005-06-08
In a high intensity circular accelerator the synchrotron dynamics introduces a slow modulation in the betatronic tune due to the space-charge tune depression. When the transverse motion is non-linear due to the presence of multipolar effects, resonance islands move in the phase space and change their amplitude. This effect introduces the trapping and detrapping phenomenon and a slow diffusion in the phase space. We apply the neo-adiabatic theory to describe this diffusion mechanism that can contribute to halo formation.
NASA Astrophysics Data System (ADS)
Tian, Si-Cong; Wan, Ren-Gang; Wang, Chun-Liang; Shu, Shi-Li; Wang, Li-Jie; Tong, Chun-Zhu
2016-04-01
We propose a scheme for creation and transfer of coherence among ground state and indirect exciton states of triple quantum dots via the technique of stimulated Raman adiabatic passage. Compared with the traditional stimulated Raman adiabatic passage, the Stokes laser pulse is replaced by the tunneling pulse, which can be controlled by the externally applied voltages. By varying the amplitudes and sequences of the pump and tunneling pulses, a complete coherence transfer or an equal coherence distribution among multiple states can be obtained. The investigations can provide further insight for the experimental development of controllable coherence transfer in semiconductor structure and may have potential applications in quantum information processing.
Tian, Si-Cong; Wan, Ren-Gang; Wang, Chun-Liang; Shu, Shi-Li; Wang, Li-Jie; Tong, Chun-Zhu
2016-12-01
We propose a scheme for creation and transfer of coherence among ground state and indirect exciton states of triple quantum dots via the technique of stimulated Raman adiabatic passage. Compared with the traditional stimulated Raman adiabatic passage, the Stokes laser pulse is replaced by the tunneling pulse, which can be controlled by the externally applied voltages. By varying the amplitudes and sequences of the pump and tunneling pulses, a complete coherence transfer or an equal coherence distribution among multiple states can be obtained. The investigations can provide further insight for the experimental development of controllable coherence transfer in semiconductor structure and may have potential applications in quantum information processing. PMID:27107772
LIMB PROCESS DEVELOPMENT STUDIES
The report covers basic and applied studies concerned with three Limestone Injection Multistage Burner (LIMB) process objectives: (1) avoiding degradation of collection efficiency in the electrostatic precipitator (ESP) during LIMB, (2) achieving satisfactory sulfur dioxide (SO2)...
Silicon web process development
NASA Technical Reports Server (NTRS)
Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.
1981-01-01
The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.
Chemical waterflood process development
Chang, H.L.
1980-04-01
A waterflood process is claimed wherein a slug of biopolymer is injected into a formation, followed by a slug of synthetic polymer. The biopolymer slug protects the synthetic polymer from degradation due to presence of salts or surfactants in the formation.
Silicon web process development
NASA Technical Reports Server (NTRS)
Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Blais, P. D.; Davis, J. R., Jr.
1977-01-01
Thirty-five (35) furnace runs were carried out during this quarter, of which 25 produced a total of 120 web crystals. The two main thermal models for the dendritic growth process were completed and are being used to assist the design of the thermal geometry of the web growth apparatus. The first model, a finite element representation of the susceptor and crucible, was refined to give greater precision and resolution in the critical central region of the melt. The second thermal model, which describes the dissipation of the latent heat to generate thickness-velocity data, was completed. Dendritic web samples were fabricated into solar cells using a standard configuration and a standard process for a N(+) -P-P(+) configuration. The detailed engineering design was completed for a new dendritic web growth facility of greater width capability than previous facilities.
Development of metallization process
NASA Technical Reports Server (NTRS)
Garcia, A., III
1983-01-01
Solar cells were produced using a Mo/Sn/TiH screen printed paste with a lead/borosilicate frit that are electrically comparable to control silver cells. The process is currently unsuccessful because the soldering of interconnects to these cells has proved difficult. Future work will investigate using CO instead of H2 as the reducing gas and putting an ITO coating on the cell prior to metallization.
Development of metallization process
NASA Astrophysics Data System (ADS)
Garcia, A., III
1983-04-01
Solar cells were produced using a Mo/Sn/TiH screen printed paste with a lead/borosilicate frit that are electrically comparable to control silver cells. The process is currently unsuccessful because the soldering of interconnects to these cells has proved difficult. Future work will investigate using CO instead of H2 as the reducing gas and putting an ITO coating on the cell prior to metallization.
Adiabatic circuits: converter for static CMOS signals
NASA Astrophysics Data System (ADS)
Fischer, J.; Amirante, E.; Bargagli-Stoffi, A.; Schmitt-Landsiedel, D.
2003-05-01
Ultra low power applications can take great advantages from adiabatic circuitry. In this technique a multiphase system is used which consists ideally of trapezoidal voltage signals. The input signals to be processed will often come from a function block realized in static CMOS. The static rectangular signals must be converted for the oscillating multiphase system of the adiabatic circuitry. This work shows how to convert the input signals to the proposed pulse form which is synchronized to the appropriate supply voltage. By means of adder structures designed for a 0.13µm technology in a 4-phase system there will be demonstrated, which additional circuits are necessary for the conversion. It must be taken into account whether the data arrive in parallel or serial form. Parallel data are all in one phase and therefore it is advantageous to use an adder structure with a proper input stage, e.g. a Carry Lookahead Adder (CLA). With a serial input stage it is possible to read and to process four signals during one cycle due to the adiabatic 4-phase system. Therefore input signals with a frequency four times higher than the adiabatic clock frequency can be used. This reduces the disadvantage of the slow clock period typical for adiabatic circuits. By means of an 8 bit Ripple Carry Adder (8 bit RCA) the serial reading will be introduced. If the word width is larger than 4 bits the word can be divided in 4 bit words which are processed in parallel. This is the most efficient way to minimize the number of input lines and pads. At the same time a high throughput is achieved.
Adiabatic burst evaporation from bicontinuous nanoporous membranes
Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk
2015-01-01
Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406
Developments in Signature Process Control
NASA Astrophysics Data System (ADS)
Keller, L. B.; Dominski, Marty
1993-01-01
Developments in the adaptive process control technique known as Signature Process Control for Advanced Composites (SPCC) are described. This computer control method for autoclave processing of composites was used to develop an optimum cure cycle for AFR 700B polyamide and for an experimental poly-isoimide. An improved process cycle was developed for Avimid N polyamide. The potential for extending the SPCC technique to pre-preg quality control, press modeling, pultrusion and RTM is briefly discussed.
Silicon Web Process Development
NASA Technical Reports Server (NTRS)
Duncan, C. S.; Seidensticker, R. G.; Hopkins, R. H.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.
1978-01-01
Progress in the development of techniques to grow silicon web at 25 wq cm/min output rate is reported. Feasibility of web growth with simultaneous melt replenishment is discussed. Other factors covered include: (1) tests of aftertrimmers to improve web width; (2) evaluation of growth lid designs to raise speed and output rate; (3) tests of melt replenishment hardware; and (4) investigation of directed gas flow systems to control unwanted oxide deposition in the system and to improve convective cooling of the web. Compatibility with sufficient solar cell performance is emphasized.
Silicon web process development
NASA Technical Reports Server (NTRS)
Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hill, F. E.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.
1980-01-01
A barrier crucible design which consistently maintains melt stability over long periods of time was successfully tested and used in long growth runs. The pellet feeder for melt replenishment was operated continuously for growth runs of up to 17 hours. The liquid level sensor comprising a laser/sensor system was operated, performed well, and meets the requirements for maintaining liquid level height during growth and melt replenishment. An automated feedback loop connecting the feed mechanism and the liquid level sensing system was designed and constructed and operated successfully for 3.5 hours demonstrating the feasibility of semi-automated dendritic web growth. The sensitivity of the cost of sheet, to variations in capital equipment cost and recycling dendrites was calculated and it was shown that these factors have relatively little impact on sheet cost. Dendrites from web which had gone all the way through the solar cell fabrication process, when melted and grown into web, produce crystals which show no degradation in cell efficiency. Material quality remains high and cells made from web grown at the start, during, and the end of a run from a replenished melt show comparable efficiencies.
NASA Astrophysics Data System (ADS)
Barrett, T. B.; Marshall, R.; Bloom, J.; Comer, C.; Caulfield, J.; Warde, C.; Salour, M.
1989-11-01
This electron microscope has been applied to the study of the growth of thin epitaxial films on silicon substrates. The study of the nature of platinum-silicide films formed by heating evaporated platinum films on these substrates is discussed. The use of ultra high vacuum systems together with a residual gas analyzer (RGA) is discussed as they relate to the preparation of silicides, a dielectric layer of silicon monoxide is evaporated and an ion beam implanter is used to form a special buried layer as a step toward silicon devices. Synthesis and single crystal growth of indium phosphide in a one-step in-situ process at high ambient pressures is discussed. Analysis of heat transfer by convection, conduction, and radiation in a closed pressure vessel is given. A set of source modules and NOS procedures have been prepared to permit easy access to a 3-dimensional, non-isotrophic ray-tracing program (the Jones - Stephenson program). This system is designed to be run on a CDC CYBER computer system or equivalent using the operating system.
Processes and process development in Japan
NASA Technical Reports Server (NTRS)
Noda, T.
1986-01-01
The commercialization of solar power generation necessitates the development of low cost manufacturing method of silicon suitable for solar cells. The manufacturing methods of semiconductor grade silicon (SEG-Si) and the development of solar grade silicon (SOG-Si) in foreign countries was investigated. It was concluded that the most efficient method of developing such materials was the hydrogen reduction process of trichlorosilane (TCS), using a fluidized bed reactor. The low cost reduction of polysilicon requires cost reductions of raw materials, energy, labor, and capital. These conditions were carefully reviewed. The overall conclusion was that a development program should be based on the TCS-FBR process and that the experimental program should be conducted in test facilities capable of producing 10 tons of silicon granules per year.
Cotton, Stephen J; Miller, William H
2016-03-01
In a recent series of papers, it has been illustrated that a symmetrical quasi-classical (SQC) windowing model applied to the Meyer-Miller (MM) classical vibronic Hamiltonian provides an excellent description of a variety of electronically non-adiabatic benchmark model systems for which exact quantum results are available for comparison. In this paper, the SQC/MM approach is used to treat energy transfer dynamics in site-exciton models of light-harvesting complexes, and in particular, the well-known 7-state Fenna-Mathews-Olson (FMO) complex. Again, numerically "exact" results are available for comparison, here via the hierarchical equation of motion (HEOM) approach of Ishizaki and Fleming, and it is seen that the simple SQC/MM approach provides very reasonable agreement with the previous HEOM results. It is noted, however, that unlike most (if not all) simple approaches for treating these systems, because the SQC/MM approach presents a fully atomistic simulation based on classical trajectory simulation, it places no restrictions on the characteristics of the thermal baths coupled to each two-level site, e.g., bath spectral densities (SD) of any analytic functional form may be employed as well as discrete SD determined experimentally or from MD simulation (nor is there any restriction that the baths be harmonic), opening up the possibility of simulating more realistic variations on the basic site-exciton framework for describing the non-adiabatic dynamics of photosynthetic pigment complexes. PMID:26761191
Ultrafast stimulated Raman parallel adiabatic passage by shaped pulses
Dridi, G.; Guerin, S.; Hakobyan, V.; Jauslin, H. R.; Eleuch, H.
2009-10-15
We present a general and versatile technique of population transfer based on parallel adiabatic passage by femtosecond shaped pulses. Their amplitude and phase are specifically designed to optimize the adiabatic passage corresponding to parallel eigenvalues at all times. We show that this technique allows the robust adiabatic population transfer in a Raman system with the total pulse area as low as 3{pi}, corresponding to a fluence of one order of magnitude below the conventional stimulated Raman adiabatic passage process. This process of short duration, typically picosecond and subpicosecond, is easily implementable with the modern pulse shaper technology and opens the possibility of ultrafast robust population transfer with interesting applications in quantum information processing.
Pulse sequences in photoassociation via adiabatic passage
NASA Astrophysics Data System (ADS)
Li, Xuan; Dupre, William; Parker, Gregory A.
2012-07-01
We perform a detailed study of pulse sequences in a photoassociation via adiabatic passage (PAP) process to transfer population from an ensemble of ultracold atomic clouds to a vibrationally cold molecular state. We show that an appreciable final population of ultracold NaCs molecules can be achieved with optimized pulses in either the ‘counter-intuitive’ (tP > tS) or ‘intuitive’ (tP < tS) PAP pulse sequences, with tP and tS denoting the temporal centers of the pump and Stokes pulses, respectively. By investigating the dependence of the reactive yield on pulse sequences, in a wide range of tP-tS, we show that there is not a fundamental preference to either pulse sequence in a PAP process. We explain this no-sequence-preference phenomenon by analyzing a multi-bound model so that an analogy can be drawn to the conventional stimulated Raman adiabatic passage.
NASA Astrophysics Data System (ADS)
Liang, H.; Ashour-Abdalla, M.; Richard, R. L.; Schriver, D.; El-Alaoui, M.; Walker, R. J.
2013-12-01
We investigate the spatial evolution of energetic electron distribution functions in the near-Earth plasma sheet associated with earthward propagating dipolarization fronts by using in situ observations as well as magnetohydrodynamic (MHD) and large scale kinetic (LSK) simulations. We have investigated two substorms, one on February 15, 2008 and the other on August 15, 2001. The February 15 event was observed by one of the THEMIS spacecraft at X_{GSM} -10RE, while the August 15 event was observed by Cluster at X -18RE. Both the MHD and LSK simulation results are compared to these spacecraft observations. Earthward propagating dipolarization fronts are found in both the observations and the MHD simulations, which exhibit very different magnetotail configurations, with contrasting flows, magnetic reconnection configuration, and plasma sheet structure. Electron LSK simulations were performed by using the time-varying magnetic and electric fields from the global MHD simulations. For the February 15, 2008 event, the electrons were launched near X = -20 RE with a thermal energy of 1 keV and for August 15, 2001 event, they were launched at 4 keV near X = -22 RE. These electrons undergo both non-adiabatic acceleration near the magnetotail reconnection region and adiabatic acceleration as they propagate earthward from the launch region. We compute the electron distribution functions parallel and perpendicular to the magnetic field at different locations between X = -18 RE and X = -10 RE in the plasma sheet. We find that for the February 15, 2008 event, reconnection is localized with a narrow region of high-speed flows ( 300 km/s). For this event the distribution functions show mainly f(v_perp) > f(v_par) ("par" and "perp" correspond to parallel and perpendicular to magnetic field). On August 15, 2001, there is a neutral line extending across the tail with relatively low-speed flows ( 100 km/s). For this event the distribution functions show mainly f(v_par) > f(v_perp). The
NASA Astrophysics Data System (ADS)
Joyes, P.; Tarento, R. J.; Van de Walle, J.
1997-06-01
The non-adiabatic time-dependent reaction of valence electrons in media submitted to a violent perturbation has important consequences in monoatomic fragmentation. We study these effects for various fullerenes: C20, C60, C70 and C110. The ionization probability P(K) of a monoatomic fragment with kinetic K energy is investigated for C20, C60, C70 and C110. Our results show that there is no important variation of P(K) with size but, for a given size, P(K) may depend on the initial position of the ejected atom. We give the variation with time of the population on the ejected atom and on various substrate levels. We also study the electronic currents appearing during the phenomenon.
Developing the JPL Engineering Processes
NASA Technical Reports Server (NTRS)
Linick, Dave; Briggs, Clark
2004-01-01
This paper briefly recounts the recent history of process reengineering at the NASA Jet Propulsion Laboratory, with a focus on the engineering processes. The JPL process structure is described and the process development activities of the past several years outlined. The main focus of the paper is on the current process structure, the emphasis on the flight project life cycle, the governance approach that lead to Flight Project Practices, and the remaining effort to capture process knowledge at the detail level of the work group.
Nonadiabatic transitions in finite-time adiabatic rapid passage
NASA Astrophysics Data System (ADS)
Lu, T.; Miao, X.; Metcalf, H.
2007-06-01
To apply the adiabatic rapid passage process repetitively [T. Lu, X. Miao, and H. Metcalf, Phys. Rev. A 71, 061405(R) (2005)], the nonadiabatic transition probability of a two-level atom subject to chirped light pulses over a finite period of time needs to be calculated. Using a unitary first-order perturbation method in the rotating adiabatic frame, an approximate formula has been derived for such transition probabilities in the entire parameter space of the pulses.
Shortcuts to adiabaticity for non-Hermitian systems
Ibanez, S.; Martinez-Garaot, S.; Torrontegui, E.; Muga, J. G.; Chen Xi
2011-08-15
Adiabatic processes driven by non-Hermitian, time-dependent Hamiltonians may be sped up by generalizing inverse engineering techniques based on counter-diabatic (transitionless driving) algorithms or on dynamical invariants. We work out the basic theory and examples described by two-level Hamiltonians: the acceleration of rapid adiabatic passage with a decaying excited level and of the dynamics of a classical particle on an expanding harmonic oscillator.
Shortcuts to adiabaticity from linear response theory.
Acconcia, Thiago V; Bonança, Marcus V S; Deffner, Sebastian
2015-10-01
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. With the help of phenomenological response functions, a simple expression for the excess work is found-quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. Finally, we propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times. PMID:26565209
Shortcuts to adiabaticity from linear response theory
NASA Astrophysics Data System (ADS)
Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian
2015-10-01
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. With the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. Finally, we propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times.
Shortcuts to adiabaticity from linear response theory
Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian
2015-10-23
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times.
Shortcuts to adiabaticity from linear response theory
Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian
2015-10-23
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts tomore » adiabaticity for specific and very short driving times.« less
Adiabatic state preparation study of methylene
Veis, Libor Pittner, Jiří
2014-06-07
Quantum computers attract much attention as they promise to outperform their classical counterparts in solving certain type of problems. One of them with practical applications in quantum chemistry is simulation of complex quantum systems. An essential ingredient of efficient quantum simulation algorithms are initial guesses of the exact wave functions with high enough fidelity. As was proposed in Aspuru-Guzik et al. [Science 309, 1704 (2005)], the exact ground states can in principle be prepared by the adiabatic state preparation method. Here, we apply this approach to preparation of the lowest lying multireference singlet electronic state of methylene and numerically investigate preparation of this state at different molecular geometries. We then propose modifications that lead to speeding up the preparation process. Finally, we decompose the minimal adiabatic state preparation employing the direct mapping in terms of two-qubit interactions.
Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling
NASA Technical Reports Server (NTRS)
Chu, Paul C. W.
2004-01-01
The research at Houston was focused on optimizing the design of superconducting magnets for advanced adiabatic demagnetization refrigerators (ADRs), assessing the feasibility of using high temperature superconducting (HTS) magnets in ADRs in the future, and developing techniques to deposit HTS thin and thick films on high strength, low thermal conductivity substrates for HTS magnet leads. Several approaches have been tested for the suggested superconducting magnets.
Computer Code For Turbocompounded Adiabatic Diesel Engine
NASA Technical Reports Server (NTRS)
Assanis, D. N.; Heywood, J. B.
1988-01-01
Computer simulation developed to study advantages of increased exhaust enthalpy in adiabatic turbocompounded diesel engine. Subsytems of conceptual engine include compressor, reciprocator, turbocharger turbine, compounded turbine, ducting, and heat exchangers. Focus of simulation of total system is to define transfers of mass and energy, including release and transfer of heat and transfer of work in each subsystem, and relationship among subsystems. Written in FORTRAN IV.
Monolithic Fuel Fabrication Process Development
C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight
2006-05-01
The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.
Quantum adiabatic evolution with energy degeneracy levels
NASA Astrophysics Data System (ADS)
Zhang, Qi
2016-01-01
A classical-kind phase-space formalism is developed to address the tiny intrinsic dynamical deviation from what is predicted by Wilczek-Zee theorem during quantum adiabatic evolution on degeneracy levels. In this formalism, the Hilbert space and the aggregate of degenerate eigenstates become the classical-kind phase space and a high-dimensional subspace in the phase space, respectively. Compared with the previous analogous study by a different method, the current result is qualitatively different in that the first-order deviation derived here is always perpendicular to the degeneracy subspace. A tripod-scheme Hamiltonian with two degenerate dark states is employed to illustrate the adiabatic deviation with degeneracy levels.
Quantum Monte Carlo simulations of tunneling in quantum adiabatic optimization
NASA Astrophysics Data System (ADS)
Brady, Lucas T.; van Dam, Wim
2016-03-01
We explore to what extent path-integral quantum Monte Carlo methods can efficiently simulate quantum adiabatic optimization algorithms during a quantum tunneling process. Specifically we look at symmetric cost functions defined over n bits with a single potential barrier that a successful quantum adiabatic optimization algorithm will have to tunnel through. The height and width of this barrier depend on n , and by tuning these dependencies, we can make the optimization algorithm succeed or fail in polynomial time. In this article we compare the strength of quantum adiabatic tunneling with that of path-integral quantum Monte Carlo methods. We find numerical evidence that quantum Monte Carlo algorithms will succeed in the same regimes where quantum adiabatic optimization succeeds.
Processes of Expressive Behavior Development.
ERIC Educational Resources Information Center
Zivin, Gail
1986-01-01
Seventeen processes in the development of expressive behavior are reviewed and coordinated in a framework that is shown to accommodate current perspectives on expressive behavior development. Works of Ekman, Izard, Lewis and Michalson, and Sroufe are briefly reviewed. Neglected areas of research are indicated and the course of expressive behavior…
Automating the training development process
NASA Technical Reports Server (NTRS)
Scott, Carol J.
1993-01-01
The Automated Training Development System (ATDS) was developed as a training tool for the JPL training environment. ATDS is based on the standard for military training programs and is designed to develop training from a system perspective, focusing on components in terms of the whole process. The principal feature of ATDS is data base maintainability. Everything is contained and maintained within the data base, and, if properly developed, it could be a training component of a software delivery and provided to CM as a controlled item. The analysis, development, design, presentation, and reporting phases in the ATDS instructional design method are illustrated.
Scale-up of mild gasification to a process development unit
Campbell, J.A.L.; Carty, R.H.; Saladin, N.; Foster, H.
1992-06-01
The work performed during the second quarterly reporting period (February 21 through May 20, 1992) on the research program, Scale-Up of Mild Gasification to a Process Development Unit'' is presented in this report. The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: (1) design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup. (2) obtain large batches of coal-derived co-products for industrial evaluation. (3) prepare a detailed design of a demonstration unit. (4) develop technical and economic plans for commercialization of the MILDGAS process. The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300[degrees]F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The PDU to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of char, coal liquids, and gases; a thermal cracker for upgrading of the coal liquids; and a hot briquetting unit for the production of form coke and smokeless fuel briquettes. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste.
Acceleration of adiabatic quantum dynamics in electromagnetic fields
Masuda, Shumpei; Nakamura, Katsuhiro
2011-10-15
We show a method to accelerate quantum adiabatic dynamics of wave functions under electromagnetic field (EMF) by developing the preceding theory [Masuda and Nakamura, Proc. R. Soc. London Ser. A 466, 1135 (2010)]. Treating the orbital dynamics of a charged particle in EMF, we derive the driving field which accelerates quantum adiabatic dynamics in order to obtain the final adiabatic states in any desired short time. The scheme is consolidated by describing a way to overcome possible singularities in both the additional phase and driving potential due to nodes proper to wave functions under EMF. As explicit examples, we exhibit the fast forward of adiabatic squeezing and transport of excited Landau states with nonzero angular momentum, obtaining the result consistent with the transitionless quantum driving applied to the orbital dynamics in EMF.
Guha, S.; Kyriacou, C.; Withers, J.C.; Loutfy, R.O.
1993-04-01
Kinetic Energy penetrators made from Depleted Uranium (DU) alloys have consistently performed better than equi-density and geometrically similar penetrators made from conventional tungsten heavy alloys (WHA) during ballistic penetration tests into semi-infinite Rolled Homogeneous Armor (RHA) steel targets. The superior penetration behavior of DU penetrators is presently attributed to these penetrators maintaining a chisel nose by failure along adiabatic shear bands which is in contrast to the mushroom head observed in WHA penetrators; the mushroom head decreases the energy density at the target thereby leading to reduced penetration. The radiological hazard of DU combined with chemical corrosion during storage provides an impetus to improving the state-of-the-art in WHA with respect to ballistic penetration behavior. Interestingly, WHA penetrators with DU matrix (instead of the conventional Ni-Fe, Ni-Co, or Ni-Fe-Co matrices) also fail by adiabatic shear indicating that shear localization is probably influenced greatly by matrix material properties. Hence, an investigation into alternative matrix materials for WHA that will support shear localization is warranted.
Adiabatic evolution of plasma equilibrium
Grad, H.; Hu, P. N.; Stevens, D. C.
1975-01-01
A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included. PMID:16578729
Pressure Oscillations in Adiabatic Compression
ERIC Educational Resources Information Center
Stout, Roland
2011-01-01
After finding Moloney and McGarvey's modified adiabatic compression apparatus, I decided to insert this experiment into my physical chemistry laboratory at the last minute, replacing a problematic experiment. With insufficient time to build the apparatus, we placed a bottle between two thick textbooks and compressed it with a third textbook forced…
Adiabatic dynamics of magnetic vortices
NASA Astrophysics Data System (ADS)
Papanicolaou, N.
1994-03-01
We formulate a reasonably detailed adiabatic conjecture concerning the dynamics of skew deflection of magnetic vortices in a field gradient, which is expected to be valid at sufficiently large values of the winding number. The conjecture is consistent with the golden rule used to describe the dynamics of realistic magnetic bubbles and is verified here numerically within the 2-D isotropic Heisenberg model.
Sliding Seal Materials for Adiabatic Engines, Phase 2
NASA Technical Reports Server (NTRS)
Lankford, J.; Wei, W.
1986-01-01
An essential task in the development of the heavy-duty adiabatic diesel engine is identification and improvements of reliable, low-friction piston seal materials. In the present study, the sliding friction coefficients and wear rates of promising carbide, oxide, and nitride materials were measured under temperature, environmental, velocity, and loading conditions that are representative of the adiabatic engine environment. In addition, silicon nitride and partially stabilized zirconia disks were ion implanted with TiNi, Ni, Co, and Cr, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. In order to provide guidance needed to improve materials for this application, the program stressed fundamental understanding of the mechanisms involved in friction and wear. Electron microscopy was used to elucidate the micromechanisms of wear following wear testing, and Auger electron spectroscopy was used to evaluate interface/environment interactions which seemed to be important in the friction and wear process. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. The coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implanation of TiNi or Co. This beneficial effect was found to derive from lubricious Ti, Ni, and Co oxides.
Transitionless driving on adiabatic search algorithm
Oh, Sangchul; Kais, Sabre
2014-12-14
We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.
Transitionless driving on adiabatic search algorithm
NASA Astrophysics Data System (ADS)
Oh, Sangchul; Kais, Sabre
2014-12-01
We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.
Transitionless driving on adiabatic search algorithm.
Oh, Sangchul; Kais, Sabre
2014-12-14
We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics. PMID:25494733
Quasi-adiabatic compression heating of selected foods
NASA Astrophysics Data System (ADS)
Landfeld, Ales; Strohalm, Jan; Halama, Radek; Houska, Milan
2011-03-01
The quasi-adiabatic temperature increase due to compression heating, during high-pressure (HP) processing (HPP), was studied using specially designed equipment. The temperature increase was evaluated as the difference in temperature, during compression, between atmospheric pressure and nominal pressure. The temperature was measured using a thermocouple in the center of a polyoxymethylene cup, which contained the sample. Fresh meat balls, pork meat pate, and tomato purée temperature increases were measured at three initial temperature levels between 40 and 80 °C. Nominal pressure was either 400 or 500 MPa. Results showed that the fat content had a positive effect on temperature increases. Empirical equations were developed to calculate the temperature increase during HPP at different initial temperatures for pressures of 400 and 500 MPa. This thermal effect data can be used for numerical modeling of temperature histories of foods during HP-assisted pasteurization or sterilization processes.
Software Development Standard Processes (SDSP)
NASA Technical Reports Server (NTRS)
Lavin, Milton L.; Wang, James J.; Morillo, Ronald; Mayer, John T.; Jamshidian, Barzia; Shimizu, Kenneth J.; Wilkinson, Belinda M.; Hihn, Jairus M.; Borgen, Rosana B.; Meyer, Kenneth N.; Crean, Kathleen A.; Rinker, George C.; Smith, Thomas P.; Lum, Karen T.; Hanna, Robert A.; Erickson, Daniel E.; Gamble, Edward B., Jr.; Morgan, Scott C.; Kelsay, Michael G.; Newport, Brian J.; Lewicki, Scott A.; Stipanuk, Jeane G.; Cooper, Tonja M.; Meshkat, Leila
2011-01-01
A JPL-created set of standard processes is to be used throughout the lifecycle of software development. These SDSPs cover a range of activities, from management and engineering activities, to assurance and support activities. These processes must be applied to software tasks per a prescribed set of procedures. JPL s Software Quality Improvement Project is currently working at the behest of the JPL Software Process Owner to ensure that all applicable software tasks follow these procedures. The SDSPs are captured as a set of 22 standards in JPL s software process domain. They were developed in-house at JPL by a number of Subject Matter Experts (SMEs) residing primarily within the Engineering and Science Directorate, but also from the Business Operations Directorate and Safety and Mission Success Directorate. These practices include not only currently performed best practices, but also JPL-desired future practices in key thrust areas like software architecting and software reuse analysis. Additionally, these SDSPs conform to many standards and requirements to which JPL projects are beholden.
Technology development life cycle processes.
Beck, David Franklin
2013-05-01
This report and set of appendices are a collection of memoranda originally drafted in 2009 for the purpose of providing motivation and the necessary background material to support the definition and integration of engineering and management processes related to technology development. At the time there was interest and support to move from Capability Maturity Model Integration (CMMI) Level One (ad hoc processes) to Level Three. As presented herein, the material begins with a survey of open literature perspectives on technology development life cycles, including published data on %E2%80%9Cwhat went wrong.%E2%80%9D The main thrust of the material presents a rational expose%CC%81 of a structured technology development life cycle that uses the scientific method as a framework, with further rigor added from adapting relevant portions of the systems engineering process. The material concludes with a discussion on the use of multiple measures to assess technology maturity, including consideration of the viewpoint of potential users.
Processes and process development in Taiwan
NASA Technical Reports Server (NTRS)
Hwang, H. L.
1986-01-01
Silicon material research in the Republic of China (ROC) parallels its development in the electronic industry. A brief outline of the historical development in ROC silicon material research is given. Emphasis is placed on the recent Silane Project managed by the National Science Council, ROC, including project objectives, task forces, and recent accomplishments. An introduction is also given to industrialization of the key technologies developed in this project.
Adiabatic demagnetization refrigerator for space use
NASA Technical Reports Server (NTRS)
Serlemitsos, A. T.; Warner, B. A.; Castles, S.; Breon, S. R.; San Sebastian, M.; Hait, T.
1990-01-01
An Adiabatic Demagnetization Refrigerator (ADR) for space use is under development at NASA's Goddard Space Flight Center (GSFC). The breadboard ADR operated at 100 mK for 400 minutes. Some significant changes to that ADR, designed to eliminate shortcomings revealed during tests, are reported. To increase thermal contact, the ferric ammonium sulfate crystals were grown directly on gold-plated copper wires which serve as the thermal bus. The thermal link to the X-ray sensors was also markedly improved. To speed up the testing required to determine the best design parameters for the gas gap heat switch, the new heat switch has a modular design and is easy to disassemble.
Adiabatic Rosen-Zener interferometry with ultracold atoms
Fu Libin; Ye Defa; Lee Chaohong; Zhang Weiping; Liu Jie
2009-07-15
We propose a time-domain 'interferometer' based on double-well ultracold atoms through a so-called adiabatic Rosen-Zener process, that is, the barrier between two wells is ramped down slowly, held for a while, and then ramped back. After the adiabatic Rosen-Zener process, we count the particle population in each well. We find that the final occupation probability shows nice interference fringes. The fringe pattern is sensitive to the initial state as well as the intrinsic parameters of the system such as interatomic interaction or energy bias between two wells. The underlying mechanism is revealed and possible applications are discussed.
Development of mild gasification process
Chu, C.I.C.; Derting, T.M.
1988-07-01
Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.
Development of mild gasification process
Chu, C.I.C.; Gillespie, B.L.
1988-02-01
Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. DE-AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1-Test Plan; Task 2-Optimization of Mild Gasification Process; Task 3-Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4-Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.
Development of mild gasification process
Chu, C.I.C.; Williams, S.W.
1989-01-01
Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.
Development of mild gasification process
Chu, C.I.C.; Gillespie, B.L.
1987-11-01
Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.
Kibble-Zurek mechanism beyond adiabaticity: Finite-time scaling with critical initial slip
NASA Astrophysics Data System (ADS)
Huang, Yingyi; Yin, Shuai; Hu, Qijun; Zhong, Fan
2016-01-01
The Kibble-Zurek mechanism demands an initial adiabatic stage before an impulse stage to have a frozen correlation length that generates topological defects in a cooling phase transition. Here we study such a driven critical dynamics but with an initial condition that is near the critical point and that is far away from equilibrium. In this case, there is no initial adiabatic stage at all and thus adiabaticity is broken. However, we show that there again exists a finite length scale arising from the driving that divides the evolution into three stages. A relaxation-finite-time-scaling-adiabatic scenario is then proposed in place of the adiabatic-impulse-adiabatic scenario of the original Kibble-Zurek mechanism. A unified scaling theory, which combines finite-time scaling with critical initial slip, is developed to describe the universal behavior and is confirmed with numerical simulations of a two-dimensional classical Ising model.
Non Adiabatic Evolution of Elliptical Galaxies by Dynamical Friction
NASA Astrophysics Data System (ADS)
Arena, S. E.; Bertin, G.; Liseikina, T.; Pegoraro, F.
2007-05-01
Many astrophysical problems, ranging from structure formation in cosmology to dynamics of elliptical galaxies, refer to slow processes of evolution of essentially collisionless self-gravitating systems. In order to determine the relevant quasi-equilibrium configuration at time t from given initial conditions, it is often argued that such slow evolution may be approximated in terms of adiabatic evolution, for the calculation of which efficient semi--analytical techniques are available. Here we focus on the slow process of evolution, induced by dynamical friction of a host stellar system on a minority component of "satellites", to determine to what extent an adiabatic description might be applied. The study is realized by means of N--body simulations of the evolution of the total system (the stellar system plus the minority component), in a controlled numerical environment. In particular, we compare the evolution from initial to final configurations of the system subject to dynamical friction with that of the same system evolved adiabatically (in the absence of dynamical friction). We consider two classes of galaxy models characterized by significantly different density and pressure anisotropy profiles. We demonstrate that, for the examined process, the evolution driven by dynamical friction is significantly different from the adiabatic case, not only quantitatively, but also qualitatively. The two classes of galaxy models considered in this investigation exhibit generally similar trends in evolution, with one exception: concentrated models reach a final total density profile, in the internal region, shallower than the initial one, while galaxy models with a broad core show the opposite behaviour. The evolution of elliptical galaxies induced by dynamical friction is a slow process but it is not adiabatic. The results of our investigation should be taken as a warning against the indiscriminate use of adiabatic growth prescriptions in studies of the structure of
Adiabaticity in open quantum systems
NASA Astrophysics Data System (ADS)
Venuti, Lorenzo Campos; Albash, Tameem; Lidar, Daniel A.; Zanardi, Paolo
2016-03-01
We provide a rigorous generalization of the quantum adiabatic theorem for open systems described by a Markovian master equation with time-dependent Liouvillian L (t ) . We focus on the finite system case relevant for adiabatic quantum computing and quantum annealing. Adiabaticity is defined in terms of closeness to the instantaneous steady state. While the general result is conceptually similar to the closed-system case, there are important differences. Namely, a system initialized in the zero-eigenvalue eigenspace of L (t ) will remain in this eigenspace with a deviation that is inversely proportional to the total evolution time T . In the case of a finite number of level crossings, the scaling becomes T-η with an exponent η that we relate to the rate of the gap closing. For master equations that describe relaxation to thermal equilibrium, we show that the evolution time T should be long compared to the corresponding minimum inverse gap squared of L (t ) . Our results are illustrated with several examples.
Spatial adiabatic passage via interaction-induced band separation
NASA Astrophysics Data System (ADS)
Benseny, Albert; Gillet, Jérémie; Busch, Thomas
2016-03-01
The development of advanced quantum technologies and the quest for a deeper understanding of many-particle quantum mechanics requires control over the quantum state of interacting particles to a high degree of fidelity. However, the quickly increasing density of the spectrum, together with the appearance of crossings in time-dependent processes, makes any effort to control the system hard and resource intensive. Here we show that in trapped systems regimes can exist in which isolated energy bands appear that allow one to easily generalize known single-particle techniques. We demonstrate this for the well-known spatial adiabatic passage effect, which can control the center-of-mass state of atoms with high fidelity.
Process Development for Nanostructured Photovoltaics
Elam, Jeffrey W.
2015-01-01
Photovoltaic manufacturing is an emerging industry that promises a carbon-free, nearly limitless source of energy for our nation. However, the high-temperature manufacturing processes used for conventional silicon-based photovoltaics are extremely energy-intensive and expensive. This high cost imposes a critical barrier to the widespread implementation of photovoltaic technology. Argonne National Laboratory and its partners recently invented new methods for manufacturing nanostructured photovoltaic devices that allow dramatic savings in materials, process energy, and cost. These methods are based on atomic layer deposition, a thin film synthesis technique that has been commercialized for the mass production of semiconductor microelectronics. The goal of this project was to develop these low-cost fabrication methods for the high efficiency production of nanostructured photovoltaics, and to demonstrate these methods in solar cell manufacturing. We achieved this goal in two ways: 1) we demonstrated the benefits of these coatings in the laboratory by scaling-up the fabrication of low-cost dye sensitized solar cells; 2) we used our coating technology to reduce the manufacturing cost of solar cells under development by our industrial partners.
NASA Astrophysics Data System (ADS)
Li, Dafa
2016-05-01
The adiabatic theorem was proposed about 90 years ago and has played an important role in quantum physics. The quantitative adiabatic condition constructed from eigenstates and eigenvalues of a Hamiltonian is a traditional tool to estimate adiabaticity and has proven to be the necessary and sufficient condition for adiabaticity. However, recently the condition has become a controversial subject. In this paper, we list some expressions to estimate the validity of the adiabatic approximation. We show that the quantitative adiabatic condition is invalid for the adiabatic approximation via the Euclidean distance between the adiabatic state and the evolution state. Furthermore, we deduce general necessary and sufficient conditions for the validity of the adiabatic approximation by different definitions.
Shortcuts to adiabaticity in a time-dependent box
Campo, A. del; Boshier, M. G.
2012-01-01
A method is proposed to drive an ultrafast non-adiabatic dynamics of an ultracold gas trapped in a time-dependent box potential. The resulting state is free from spurious excitations associated with the breakdown of adiabaticity, and preserves the quantum correlations of the initial state up to a scaling factor. The process relies on the existence of an adiabatic invariant and the inversion of the dynamical self-similar scaling law dictated by it. Its physical implementation generally requires the use of an auxiliary expulsive potential. The method is extended to a broad family of interacting many-body systems. As illustrative examples we consider the ultrafast expansion of a Tonks-Girardeau gas and of Bose-Einstein condensates in different dimensions, where the method exhibits an excellent robustness against different regimes of interactions and the features of an experimentally realizable box potential. PMID:22970340
Classical nuclear motion coupled to electronic non-adiabatic transitions
NASA Astrophysics Data System (ADS)
Agostini, Federica; Abedi, Ali; Gross, E. K. U.
2014-12-01
Based on the exact factorization of the electron-nuclear wave function, we have recently proposed a mixed quantum-classical scheme [A. Abedi, F. Agostini, and E. K. U. Gross, Europhys. Lett. 106, 33001 (2014)] to deal with non-adiabatic processes. Here we present a comprehensive description of the formalism, including the full derivation of the equations of motion. Numerical results are presented for a model system for non-adiabatic charge transfer in order to test the performance of the method and to validate the underlying approximations.
Classical nuclear motion coupled to electronic non-adiabatic transitions
Agostini, Federica; Abedi, Ali; Gross, E. K. U.
2014-12-07
Based on the exact factorization of the electron-nuclear wave function, we have recently proposed a mixed quantum-classical scheme [A. Abedi, F. Agostini, and E. K. U. Gross, Europhys. Lett. 106, 33001 (2014)] to deal with non-adiabatic processes. Here we present a comprehensive description of the formalism, including the full derivation of the equations of motion. Numerical results are presented for a model system for non-adiabatic charge transfer in order to test the performance of the method and to validate the underlying approximations.
Nonadiabatic Transitions in Adiabatic Rapid Passage
NASA Astrophysics Data System (ADS)
Lu, T.; Miao, X.; Metcalf, H.
2006-05-01
Optical forces much larger than the ordinary radiative force can be achieved on a two-level atom by multiple repetitions of adiabatic rapid passage sweeps with counterpropagating light beams. Chirped light pulses drive the atom-laser system up a ladder of dressed state energy sheets on sequential trajectories, thereby decreasing the atomic kinetic energy. Nonadiabatic transitions between the energy sheets must be avoided for this process to be effective. We have calculated the nonadiabatic transition probability for various chirped light pulses numerically. These results were compared to the first Demkov-Kunike model and the well-known Landau-Zener model. In addition, an analytical form of the nonadiabatic transition probability has been found for linearly chirped pulses and an approximate form for generic symmetric finite-time pulses has been found for the entire parameter space using the technique of unitary integration. From this, the asymptotic transition probability in the adiabatic limit was derived. T. Lu, X. Miao, and H. Metcalf, Phys., Rev. A 71 061405(R) (2005). Yu. Demkov and M. Kunike, Vestn. Leningr. Univ. Fis. Khim., 16, 39 (1969); K.-A. Suominen and B. Garraway, Phys. Rev. A45, 374 (1992)
Adiabatic Mass Loss Model in Binary Stars
NASA Astrophysics Data System (ADS)
Ge, H. W.
2012-07-01
Rapid mass transfer process in the interacting binary systems is very complicated. It relates to two basic problems in the binary star evolution, i.e., the dynamically unstable Roche-lobe overflow and the common envelope evolution. Both of the problems are very important and difficult to be modeled. In this PhD thesis, we focus on the rapid mass loss process of the donor in interacting binary systems. The application to the criterion of dynamically unstable mass transfer and the common envelope evolution are also included. Our results based on the adiabatic mass loss model could be used to improve the binary evolution theory, the binary population synthetic method, and other related aspects. We build up the adiabatic mass loss model. In this model, two approximations are included. The first one is that the energy generation and heat flow through the stellar interior can be neglected, hence the restructuring is adiabatic. The second one is that he stellar interior remains in hydrostatic equilibrium. We model this response by constructing model sequences, beginning with a donor star filling its Roche lobe at an arbitrary point in its evolution, holding its specific entropy and composition profiles fixed. These approximations are validated by the comparison with the time-dependent binary mass transfer calculations and the polytropic model for low mass zero-age main-sequence stars. In the dynamical time scale mass transfer, the adiabatic response of the donor star drives it to expand beyond its Roche lobe, leading to runaway mass transfer and the formation of a common envelope with its companion star. For donor stars with surface convection zones of any significant depth, this runaway condition is encountered early in mass transfer, if at all; but for main sequence stars with radiative envelopes, it may be encountered after a prolonged phase of thermal time scale mass transfer, so-called delayed dynamical instability. We identify the critical binary mass ratio for the
A Kinetic Study of the Adiabatic Polymerization of Acrylamide.
ERIC Educational Resources Information Center
Thomson, R. A. M.
1986-01-01
Discusses theory, procedures, and results for an experiment which demonstrates the application of basic physics to chemical problems. The experiment involves the adiabatic process, in which polymerization carried out in a vacuum flask is compared to the theoretical prediction of the model with the temperature-time curve obtained in practice. (JN)
Fast Quasi-Adiabatic Gas Cooling: An Experiment Revisited
ERIC Educational Resources Information Center
Oss, S.; Gratton, L. M.; Calza, G.; Lopez-Arias, T.
2012-01-01
The well-known experiment of the rapid expansion and cooling of the air contained in a bottle is performed with a rapidly responsive, yet very cheap thermometer. The adiabatic, low temperature limit is approached quite closely and measured with our apparatus. A straightforward theoretical model for this process is also presented and discussed.…
When an Adiabatic Irreversible Expansion or Compression Becomes Reversible
ERIC Educational Resources Information Center
Anacleto, Joaquim; Ferreira, J. M.; Soares, A. A.
2009-01-01
This paper aims to contribute to a better understanding of the concepts of a "reversible process" and "entropy". For this purpose, an adiabatic irreversible expansion or compression is analysed, by considering that an ideal gas is expanded (compressed), from an initial pressure P[subscript i] to a final pressure P[subscript f], by being placed in…
Pressure sensitivity of adiabatic shear banding in metals
NASA Astrophysics Data System (ADS)
Hanina, E.; Rittel, D.; Rosenberg, Z.
2007-01-01
Adiabatic shear banding (ASB) is a dynamic failure mode characterized by large plastic strains in a narrow localized band. ASB occurs at high strain rates (ɛ˙⩾103s-1), under adiabatic conditions leading to a significant temperature rise inside the band [H. Tresca, Annales du Conservatoire des Arts et Métiers 4, (1879); Y. L. Bai and B. Dodd, Adiabatic Shear Localization-Occurrence, Theories, and Applications (Pergamon, Oxford, 1992); M. A. Meyers, Dynamic Behavior of Materials (Wiley, New York, 1994).; and J. J. Lewandowski and L. M. Greer, Nat. Mater. 5, 15 (2006)]. Large hydrostatic pressures are experienced in many dynamic applications involving ASB formation (e.g., ballistic penetration, impact, and machining). The relationship between hydrostatic pressure and ASB development remains an open question, although its importance has been often noted. This letter reports original experimental results indicating a linear relationship between the (normalized) dynamic deformation energy and the (normalized) hydrostatic pressure.
Effect of the Heat Pipe Adiabatic Region.
Brahim, Taoufik; Jemni, Abdelmajid
2014-04-01
The main motivation of conducting this work is to present a rigorous analysis and investigation of the potential effect of the heat pipe adiabatic region on the flow and heat transfer performance of a heat pipe under varying evaporator and condenser conditions. A two-dimensional steady-state model for a cylindrical heat pipe coupling, for both regions, is presented, where the flow of the fluid in the porous structure is described by Darcy-Brinkman-Forchheimer model which accounts for the boundary and inertial effects. The model is solved numerically by using the finite volumes method, and a fortran code was developed to solve the system of equations obtained. The results show that a phase change can occur in the adiabatic region due to temperature gradient created in the porous structure as the heat input increases and the heat pipe boundary conditions change. A recirculation zone may be created at the condenser end section. The effect of the heat transfer rate on the vapor radial velocities and the performance of the heat pipe are discussed. PMID:24895467
Sliding seal materials for adiabatic engines
NASA Technical Reports Server (NTRS)
Lankford, J.
1985-01-01
The sliding friction coefficients and wear rates of promising carbide, oxide, and nitride materials were measured under temperature, environmental, velocity, loading conditions that are representative of the adiabatic engine environment. In order to provide guidance needed to improve materials for this application, the program stressed fundamental understanding of the mechanisms involved in friction and wear. Microhardness tests were performed on the candidate materials at elevated temperatures, and in atmospheres relevant to the piston seal application, and optical and electron microscopy were used to elucidate the micromechanisms of wear following wear testing. X-ray spectroscopy was used to evaluate interface/environment interactions which seemed to be important in the friction and wear process. Electrical effects in the friction and wear processes were explored in order to evaluate the potential usefulness of such effects in modifying the friction and wear rates in service. However, this factor was found to be of negligible significance in controlling friction and wear.
Adiabatic Wankel type rotary engine
NASA Technical Reports Server (NTRS)
Kamo, R.; Badgley, P.; Doup, D.
1988-01-01
This SBIR Phase program accomplished the objective of advancing the technology of the Wankel type rotary engine for aircraft applications through the use of adiabatic engine technology. Based on the results of this program, technology is in place to provide a rotor and side and intermediate housings with thermal barrier coatings. A detailed cycle analysis of the NASA 1007R Direct Injection Stratified Charge (DISC) rotary engine was performed which concluded that applying thermal barrier coatings to the rotor should be successful and that it was unlikely that the rotor housing could be successfully run with thermal barrier coatings as the thermal stresses were extensive.
Quantum dynamics by the constrained adiabatic trajectory method
Leclerc, A.; Jolicard, G.; Guerin, S.; Killingbeck, J. P.
2011-03-15
We develop the constrained adiabatic trajectory method (CATM), which allows one to solve the time-dependent Schroedinger equation constraining the dynamics to a single Floquet eigenstate, as if it were adiabatic. This constrained Floquet state (CFS) is determined from the Hamiltonian modified by an artificial time-dependent absorbing potential whose forms are derived according to the initial conditions. The main advantage of this technique for practical implementation is that the CFS is easy to determine even for large systems since its corresponding eigenvalue is well isolated from the others through its imaginary part. The properties and limitations of the CATM are explored through simple examples.
Speeding up Adiabatic Quantum State Transfer by Using Dressed States
NASA Astrophysics Data System (ADS)
Baksic, Alexandre; Ribeiro, Hugo; Clerk, Aashish A.
2016-06-01
We develop new pulse schemes to significantly speed up adiabatic state transfer protocols. Our general strategy involves adding corrections to an initial control Hamiltonian that harness nonadiabatic transitions. These corrections define a set of dressed states that the system follows exactly during the state transfer. We apply this approach to stimulated Raman adiabatic passage protocols and show that a suitable choice of dressed states allows one to design fast protocols that do not require additional couplings, while simultaneously minimizing the occupancy of the "intermediate" level.
Spatial adiabatic passage: a review of recent progress
NASA Astrophysics Data System (ADS)
Menchon-Enrich, R.; Benseny, A.; Ahufinger, V.; Greentree, A. D.; Busch, Th; Mompart, J.
2016-07-01
Adiabatic techniques are known to allow for engineering quantum states with high fidelity. This requirement is currently of large interest, as applications in quantum information require the preparation and manipulation of quantum states with minimal errors. Here we review recent progress on developing techniques for the preparation of spatial states through adiabatic passage, particularly focusing on three state systems. These techniques can be applied to matter waves in external potentials, such as cold atoms or electrons, and to classical waves in waveguides, such as light or sound.
Spatial adiabatic passage: a review of recent progress.
Menchon-Enrich, R; Benseny, A; Ahufinger, V; Greentree, A D; Busch, Th; Mompart, J
2016-07-01
Adiabatic techniques are known to allow for engineering quantum states with high fidelity. This requirement is currently of large interest, as applications in quantum information require the preparation and manipulation of quantum states with minimal errors. Here we review recent progress on developing techniques for the preparation of spatial states through adiabatic passage, particularly focusing on three state systems. These techniques can be applied to matter waves in external potentials, such as cold atoms or electrons, and to classical waves in waveguides, such as light or sound. PMID:27245462
Quantum and classical non-adiabatic dynamics of Li_{2}^{+}Ne photodissociation
NASA Astrophysics Data System (ADS)
Pouilly, Brigitte; Monnerville, Maurice; Zanuttini, David; Gervais, Benoît
2015-01-01
The 3D photodissociation dynamics of Li2+Ne system is investigated by quantum calculations using the multi-configuration time-dependent Hartree (MCTDH) method and by classical simulations with the trajectory surface hopping (TSH) approach. Six electronic states of A’ symmetry and two states of A” symmetry are involved in the process. Couplings in the excitation region and two conical intersections in the vicinity of the Franck-Condon zone control the non-adiabatic nuclear dynamics. A diabatic representation including all the states and the couplings is determined. Diabatic and adiabatic populations calculated for initial excitation to pure diabatic and adiabatic states lead to a clear understanding of the mechanisms governing the non-adiabatic photodissociation process. The classical and quantum photodissociation cross-sections for absorption in two adiabatic states of the A’ symmetry are calculated. A remarkable agreement between quantum and classical results is obtained regarding the populations and the absorption cross-sections.
Scaleup of mild gasification to be a process development. Quarterly report, February 1995--May 1995
Doane, E.P.; Carty, R.H.; Foster, H.
1995-06-01
The work performed during the Fourteenth quarterly reporting period (February 21 through May 20, 1995) on the research program, {open_quotes}Scale-Up of Mild Gasification to a Process Development Unit{close_quotes} is presented in this report. The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: (1) design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup; (2) obtain large batches of coal-derived co-products for industrial evaluation; (3) prepare a detailed design of a demonstration unit; and (4) develop technical and economic plans for commercialization of the MILDGAS process. The project team that is performing the initial phases of the PDU development are: Kerr-McGee Coal Corporation (K-M Coal), the Institute of Gas Technology (IGT), Bechtel Corporation (Bechtel), and Southern Illinois University at Carbondale (SIUC). The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300{degrees}F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The 1 ton/hr PDU facility that is to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of gases, coal liquids, and char; a three-stage condensation train to condense and store the liquid products; and coal feeding and char handling equipment. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste. This quarter, the formal HAZOP review was completed and a report detailing action items for resolution by the parties responsible was prepared.
The adiabatic phase mixing and heating of electrons in Buneman turbulence
Che, H.; Goldstein, M. L.; Drake, J. F.; Swisdak, M.
2013-06-15
The nonlinear development of the strong Buneman instability and the associated fast electron heating in thin current layers with Ω{sub e}/ω{sub pe}<1 is explored. Phase mixing of the electrons in wave potential troughs and a rapid increase in temperature are observed during the saturation of the instability. We show that the motion of trapped electrons can be described using a Hamiltonian formalism in the adiabatic approximation. The process of separatrix crossing as electrons are trapped and de-trapped is irreversible and guarantees that the resulting electron energy gain is a true heating process.
Campbell, J.A.L.; Carty, R.H.; Saladin, N.; Foster, H.
1992-06-01
The work performed during the second quarterly reporting period (February 21 through May 20, 1992) on the research program, ``Scale-Up of Mild Gasification to a Process Development Unit`` is presented in this report. The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: (1) design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup. (2) obtain large batches of coal-derived co-products for industrial evaluation. (3) prepare a detailed design of a demonstration unit. (4) develop technical and economic plans for commercialization of the MILDGAS process. The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300{degrees}F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The PDU to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of char, coal liquids, and gases; a thermal cracker for upgrading of the coal liquids; and a hot briquetting unit for the production of form coke and smokeless fuel briquettes. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste.
Symmetry-protected adiabatic quantum transistors
NASA Astrophysics Data System (ADS)
Williamson, Dominic J.; Bartlett, Stephen D.
2015-05-01
Adiabatic quantum transistors (AQT) allow quantum logic gates to be performed by applying a large field to a quantum many-body system prepared in its ground state, without the need for local control. The basic operation of such a device can be viewed as driving a spin chain from a symmetry-protected (SP) phase to a trivial phase. This perspective offers an avenue to generalize the AQT and to design several improvements. The performance of quantum logic gates is shown to depend only on universal symmetry properties of a SP phase rather than any fine tuning of the Hamiltonian, and it is possible to implement a universal set of logic gates in this way by combining several different types of SP matter. Such SP AQTs are argued to be robust to a range of relevant noise processes.
Adiabatic shear banding and scaling laws in chip formation with application to cutting of Ti-6Al-4V
NASA Astrophysics Data System (ADS)
Molinari, A.; Soldani, X.; Miguélez, M. H.
2013-11-01
The phenomenon of adiabatic shear banding is analyzed theoretically in the context of metal cutting. The mechanisms of material weakening that are accounted for are (i) thermal softening and (ii) material failure related to a critical value of the accumulated plastic strain. Orthogonal cutting is viewed as a unique configuration where adiabatic shear bands can be experimentally produced under well controlled loading conditions by individually tuning the cutting speed, the feed (uncut chip thickness) and the tool geometry. The role of cutting conditions on adiabatic shear banding and chip serration is investigated by combining finite element calculations and analytical modeling. This leads to the characterization and classification of different regimes of shear banding and the determination of scaling laws which involve dimensionless parameters representative of thermal and inertia effects. The analysis gives new insights into the physical aspects of plastic flow instability in chip formation. The originality with respect to classical works on adiabatic shear banding stems from the various facets of cutting conditions that influence shear banding and from the specific role exercised by convective flow on the evolution of shear bands. Shear bands are generated at the tool tip and propagate towards the chip free surface. They grow within the chip formation region while being convected away by chip flow. It is shown that important changes in the mechanism of shear banding take place when the characteristic time of shear band propagation becomes equal to a characteristic convection time. Application to Ti-6Al-4V titanium are considered and theoretical predictions are compared to available experimental data in a wide range of cutting speeds and feeds. The fundamental knowledge developed in this work is thought to be useful not only for the understanding of metal cutting processes but also, by analogy, to similar problems where convective flow is also interfering with
Does temperature increase or decrease in adiabatic decompression of magma?
NASA Astrophysics Data System (ADS)
Kilinc, A. I.; Ghiorso, M. S.; Khan, T.
2011-12-01
We have modeled adiabatic decompression of an andesitic and a basaltic magma as an isentropic process using the Melts algorithm. Our modeling shows that during adiabatic decompression temperature of andesitic magma increases but temperature of basaltic magma decreases. In an isentropic process entropy is constant so change of temperature with pressure can be written as dT/dP=T (dV/dT)/Cp where T (dV/dT)/Cp is generally positive. If delta P is negative so is delta T. In general, in the absence of phase change, we expect the temperature to decrease with adiabatic decompression. The effect of crystallization is to turn a more entropic phase (liquid) into a less entropic phase (solid), which must be compensated by raising the temperature. If during adiabatic decompression there is small amount or no crystallization, T (dV/dT)/Cp effect which lowers the temperature overwhelms the small amount of crystallization, which raises the temperature, and overall system temperature decreases.
Degenerate adiabatic perturbation theory: Foundations and applications
NASA Astrophysics Data System (ADS)
Rigolin, Gustavo; Ortiz, Gerardo
2014-08-01
We present details and expand on the framework leading to the recently introduced degenerate adiabatic perturbation theory [Phys. Rev. Lett. 104, 170406 (2010), 10.1103/PhysRevLett.104.170406], and on the formulation of the degenerate adiabatic theorem, along with its necessary and sufficient conditions [given in Phys. Rev. A 85, 062111 (2012), 10.1103/PhysRevA.85.062111]. We start with the adiabatic approximation for degenerate Hamiltonians that paves the way to a clear and rigorous statement of the associated degenerate adiabatic theorem, where the non-Abelian geometric phase (Wilczek-Zee phase) plays a central role to its quantitative formulation. We then describe the degenerate adiabatic perturbation theory, whose zeroth-order term is the degenerate adiabatic approximation, in its full generality. The parameter in the perturbative power-series expansion of the time-dependent wave function is directly associated to the inverse of the time it takes to drive the system from its initial to its final state. With the aid of the degenerate adiabatic perturbation theory we obtain rigorous necessary and sufficient conditions for the validity of the adiabatic theorem of quantum mechanics. Finally, to illustrate the power and wide scope of the methodology, we apply the framework to a degenerate Hamiltonian, whose closed-form time-dependent wave function is derived exactly, and also to other nonexactly solvable Hamiltonians whose solutions are numerically computed.
Adiabatic theory for anisotropic cold molecule collisions
Pawlak, Mariusz; Shagam, Yuval; Narevicius, Edvardas; Moiseyev, Nimrod
2015-08-21
We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment {sup 4}He(1s2s {sup 3}S) + HD(1s{sup 2}) → {sup 4}He(1s{sup 2}) + HD{sup +}(1s) + e{sup −} [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings.
Design of a spaceworthy adiabatic demagnetization refrigerator
NASA Technical Reports Server (NTRS)
Serlemitsos, A. T.; Kunes, E.; Sansebastian, M.
1992-01-01
A spaceworthy adiabatic demagnetization refrigerator (ADR) under development at NASA-Goddard is presented. A baseline model heat switch was tested extensively with an on/off ratio of about 10,000 and a parasitic heat leak of 10 micro-W. Data obtained from the breadboard models were used to design an ADR with improved structural integrity. The core of the ADR is the salt pill which consists of the paramagnetic salt crystal and the thermal bus. When a magnetic field is applied to the salt it forces the alignment of the magnetic moments, thereby decreasing the entropy of the salt. Preliminary tests results showed a net crystal mass of 680 g instead of the expected 740 g, which indicate that there are gaps in the salt pill. A partial fix was accomplished by sealing helium gas in the salt pill at a pressure of 2 bar, which improved the thermal contact during salt magnetization, at about 2 K.
Adiabatic theory for anisotropic cold molecule collisions.
Pawlak, Mariusz; Shagam, Yuval; Narevicius, Edvardas; Moiseyev, Nimrod
2015-08-21
We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment (4)He(1s2s (3)S) + HD(1s(2)) → (4)He(1s(2)) + HD(+)(1s) + e(-) [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings. PMID:26298122
Shortcut to adiabatic gate teleportation
NASA Astrophysics Data System (ADS)
Santos, Alan C.; Silva, Raphael D.; Sarandy, Marcelo S.
2016-01-01
We introduce a shortcut to the adiabatic gate teleportation model of quantum computation. More specifically, we determine fast local counterdiabatic Hamiltonians able to implement teleportation as a universal computational primitive. In this scenario, we provide the counterdiabatic driving for arbitrary n -qubit gates, which allows to achieve universality through a variety of gate sets. Remarkably, our approach maps the superadiabatic Hamiltonian HSA for an arbitrary n -qubit gate teleportation into the implementation of a rotated superadiabatic dynamics of an n -qubit state teleportation. This result is rather general, with the speed of the evolution only dictated by the quantum speed limit. In particular, we analyze the energetic cost for different Hamiltonian interpolations in the context of the energy-time complementarity.
Process Accountability in Curriculum Development.
ERIC Educational Resources Information Center
Gooler, Dennis D.; Grotelueschen, Arden
This paper urges the curriculum developer to assume the accountability for his decisions necessitated by the actual ways our society functions. The curriculum developer is encouraged to recognize that he is a salesman with a commodity (the curriculum). He is urged to realize that if he cannot market the package to the customers (the various…
Developing an Internal Processing System.
ERIC Educational Resources Information Center
DeFord, Diane
1997-01-01
The goal in Reading Recovery is to support children to develop "in the head" operations or strategies that aid them to solve problems as they read and write continuous text. To help children in organizing experience and correct any idiosyncratic or unreliable relationships, teachers must understand how children develop their internal processing…
An Instructional Systems Development Process.
ERIC Educational Resources Information Center
Campbell, Clifton P.
Instructional systems development (ISD) is a systems approach to curriculum development and instructional delivery. It is oriented toward occupational needs with an emphasis on what it is that students must learn to perform specific tasks, what facilities best provide a setting for the neccessary learning, and what instructional methods and media…
Quantum gates with controlled adiabatic evolutions
NASA Astrophysics Data System (ADS)
Hen, Itay
2015-02-01
We introduce a class of quantum adiabatic evolutions that we claim may be interpreted as the equivalents of the unitary gates of the quantum gate model. We argue that these gates form a universal set and may therefore be used as building blocks in the construction of arbitrary "adiabatic circuits," analogously to the manner in which gates are used in the circuit model. One implication of the above construction is that arbitrary classical boolean circuits as well as gate model circuits may be directly translated to adiabatic algorithms with no additional resources or complexities. We show that while these adiabatic algorithms fail to exhibit certain aspects of the inherent fault tolerance of traditional quantum adiabatic algorithms, they may have certain other experimental advantages acting as quantum gates.
On a Nonlinear Model in Adiabatic Evolutions
NASA Astrophysics Data System (ADS)
Sun, Jie; Lu, Song-Feng
2016-08-01
In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully solve the problem, while the linear model can not. Also in the same setting, when the overlap between the initial state and the final stare is sufficiently large, a simple linear adiabatic evolution can achieve O(1) time efficiency, but infinite time complexity for the nonlinear model of adiabatic evolution is needed. This tells us, it is not always a wise choice to use nonlinear interpolations in adiabatic algorithms. Sometimes, simple linear adiabatic evolutions may be sufficient for using. Supported by the National Natural Science Foundation of China under Grant Nos. 61402188 and 61173050. The first author also gratefully acknowledges the support from the China Postdoctoral Science Foundation under Grant No. 2014M552041
Campbell, J.A.L.; Carty, R.H.; Saladin, N.; Foster, H.
1993-03-01
The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup obtain large batches of coal-derived co-products for industrial evaluation prepare a detailed design of a demonstration unit develop technical and economic plans for commercialization of the MILDGAS process. The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300{degree}F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The 1 ton/hr PDU facility that is to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of gases, coal liquids, and char; a thermal cracker for upgrading of the coal liquids; a three-stage condensation train to condense and store the liquid products; and coal feeding and char handling equipment. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste.
Coutinho dos Santos, B.; Souza, C. E. R.; Dechoum, K.; Khoury, A. Z.
2007-11-15
We developed a theoretical model for the spatial mode dynamics of an optical parametric oscillator under injection of orbital angular momentum. This process is interpreted in terms of a Poincare representation of first order spatial modes. The spatial properties of the down-converted fields can be easily understood from their symmetries in this geometric representation. By considering an adiabatic mode conversion of the injected signal, we calculate the evolution of the down-converted beams. A phase conjugation effect is predicted which is a consequence of the symmetry in the Poincare sphere. We also propose an experiment to measure this effect.
Andronesi, Ovidiu C.; Ramadan, Saadallah; Mountford, Carolyn E.; Sorensen, A. Gregory
2011-01-01
Novel low-power adiabatic sequences are demonstrated for in-vivo localized two-dimensional (2D) correlated MR spectroscopy, such as COSY (Correlated Spectroscopy) and TOCSY (Total Correlated Spectroscopy). The design is based on three new elements for in-vivo 2D MRS: the use of gradient modulated constant adiabaticity GOIA-W(16,4) pulses for i) localization (COSY and TOCSY) and ii) mixing (TOCSY), and iii) the use of longitudinal mixing (z-filter) for magnetization transfer during TOCSY. GOIA-W(16,4) provides accurate signal localization, and more importantly, lowers the SAR for both TOCSY mixing and localization. Longitudinal mixing improves considerably (five-folds) the efficiency of TOCSY transfer. These are markedly different from previous 1D editing TOCSY sequences using spatially non-selective pulses and transverse mixing. Fully adiabatic (adiabatic mixing with adiabatic localization) and semi-adiabatic (adiabatic mixing with non-adiabatic localization) methods for 2D TOCSY are compared. Results are presented for simulations, phantoms, and in-vivo 2D spectra from healthy volunteers and patients with brain tumors obtained on 3T clinical platforms equipped with standard hardware. To the best of our knowledge this is the first demonstration of in-vivo adiabatic 2D TOCSY and fully adiabatic 2D COSY. It is expected that these methodological developments will advance the in-vivo applicability of multi(spectrally)dimensional MRS to reliably identify metabolic biomarkers. PMID:20890988
Managing the Software Development Process
NASA Astrophysics Data System (ADS)
Lubelczyk, J.; Parra, A.
The goal of any software development project is to produce a product that is delivered on time, within the allocated budget, and with the capabilities expected by the customer and unfortunately, this goal is rarely achieved. However, a properly managed project in a mature software engineering environment can consistently achieve this goal. In this paper we provide an introduction to three project success factors, a properly managed project, a competent project manager, and a mature software engineering environment. We will also present an overview of the benefits of a mature software engineering environment based on 24 years of data from the Software Engineering Lab, and suggest some first steps that an organization can take to begin benefiting from this environment. The depth and breadth of software engineering exceeds this paper, various references are cited with a goal of raising awareness and encouraging further investigation into software engineering and project management practices.
Managing the Software Development Process
NASA Technical Reports Server (NTRS)
Lubelczky, Jeffrey T.; Parra, Amy
1999-01-01
The goal of any software development project is to produce a product that is delivered on time, within the allocated budget, and with the capabilities expected by the customer and unfortunately, this goal is rarely achieved. However, a properly managed project in a mature software engineering environment can consistently achieve this goal. In this paper we provide an introduction to three project success factors, a properly managed project, a competent project manager, and a mature software engineering environment. We will also present an overview of the benefits of a mature software engineering environment based on 24 years of data from the Software Engineering Lab, and suggest some first steps that an organization can take to begin benefiting from this environment. The depth and breadth of software engineering exceeds this paper, various references are cited with a goal of raising awareness and encouraging further investigation into software engineering and project management practices.
Multisurface Adiabatic Reactive Molecular Dynamics.
Nagy, Tibor; Yosa Reyes, Juvenal; Meuwly, Markus
2014-04-01
Adiabatic reactive molecular dynamics (ARMD) simulation method is a surface-crossing algorithm for modeling chemical reactions in classical molecular dynamics simulations using empirical force fields. As the ARMD Hamiltonian is time dependent during crossing, it allows only approximate energy conservation. In the current work, the range of applicability of conventional ARMD is explored, and a new multisurface ARMD (MS-ARMD) method is presented, implemented in CHARMM and applied to the vibrationally induced photodissociation of sulfuric acid (H2SO4) in the gas phase. For this, an accurate global potential energy surface (PES) involving 12 H2SO4 and 4 H2O + SO3 force fields fitted to MP2/6-311G++(2d,2p) reference energies is employed. The MS-ARMD simulations conserve total energy and feature both intramolecular H-transfer reactions and water elimination. An analytical treatment of the dynamics in the crossing region finds that conventional ARMD can approximately conserve total energy for limiting cases. In one of them, the reduced mass of the system is large, which often occurs for simulations of solvated biomolecular systems. On the other hand, MS-ARMD is a general approach for modeling chemical reactions including gas-phase, homogeneous, heterogeneous, and enzymatic catalytic reactions while conserving total energy in atomistic simulations. PMID:26580356
Development of novel microencapsulation processes
NASA Astrophysics Data System (ADS)
Yin, Weisi
of polymer solution suspended in water or from a spray. Hollow PS particles were obtained by swelling PS latex with solvent, freezing in liquid nitrogen, and drying in vacuum. It is shown that the particle morphology is due to phase separation in the polymer emulsion droplets upon freezing in liquid nitrogen, and that morphological changes are driven largely by lowering interfacial free energy. The dried hollow particles were resuspended in a dispersing media and exposed to a plasticizer, which imparts mobility to polymer chains, to close the surface opening and form microcapsules surrounding an aqueous core. The interfacial free energy difference between the hydrophobic inside and hydrophilic outside surfaces is the major driving force for closing the hole on the surface. A controlled release biodegradable vehicle for drug was made by encapsulating procaine hydrochloride, a water-soluble drug, into the core of poly(DL-lactide) (PLA) microcapsules, which were made by the freeze-drying and subsequent closing process. The encapsulation efficiency is affected by the hollow particle morphology, amount of closing agent, exposure time, surfactant, and method of dispersing the hollow particles in water. Controlled release of procaine hydrochloride from the microcapsules into phosphate buffer was observed. The use of benign solvents dimethyl carbonate in spray/freeze-drying and CO2 for closing would eliminate concerns of residual harmful solvent in the product. The ease of separation of CO2 from the drug solution may also enable recycling of the drug solution to increase the overall encapsulation efficiency using these novel hollow particles.
Doane, E.P.; Carty, R.H.; Foster, H.
1995-02-01
The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup; obtain large batches of coal-derived co-products for industrial evaluation; prepare a detailed design of a demonstration unit; and develop technical and economic plans for commercialization of the MILDGAS process. The 1 ton/hr PDU facility that is to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of gases, coal liquids, and char; a three-stage condensation train to condense and store the liquid products; and coal feeding and char handling equipment. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste. This quarter work included clearing, grubbing, grading and backfilling of the site, installation of culverts and fencing, placing of the main structure foundation and truck pad, and installation of gravel on the areas that will later be blacktopped. Also this quarter, a contract for the emissions and control package was awarded to Calidus Technologies. In addition, agreement with Central Illinois Power Service on the electrical supply scope and the natural gas delivery pressure was made and the FAA waived any requirement for aircraft warning devices on the top of the structure.
Complete Cycle Experiments Using the Adiabatic Gas Law Apparatus
NASA Astrophysics Data System (ADS)
Kutzner, Mickey D.; Plantak, Mateja
2014-10-01
The ability of our society to make informed energy-usage decisions in the future depends partly on current science and engineering students retaining a deep understanding of the thermodynamics of heat engines. Teacher imaginations and equipment budgets can both be taxed in the effort to engage students in hands-on heat engine activities. The experiments described in this paper, carried out using the Adiabatic Gas Law Apparatus1 (AGLA), quantitatively explore popular complete cycle heat engine processes.
Adiabatic limits on Riemannian Heisenberg manifolds
Yakovlev, A A
2008-02-28
An asymptotic formula is obtained for the distribution function of the spectrum of the Laplace operator, in the adiabatic limit for the foliation defined by the orbits of an invariant flow on a compact Riemannian Heisenberg manifold. Bibliography: 21 titles.
General conditions for quantum adiabatic evolution
Comparat, Daniel
2009-07-15
Adiabaticity occurs when, during its evolution, a physical system remains in the instantaneous eigenstate of the Hamiltonian. Unfortunately, existing results, such as the quantum adiabatic theorem based on a slow down evolution [H({epsilon}t),{epsilon}{yields}0], are insufficient to describe an evolution driven by the Hamiltonian H(t) itself. Here we derive general criteria and exact bounds, for the state and its phase, ensuring an adiabatic evolution for any Hamiltonian H(t). As a corollary, we demonstrate that the commonly used condition of a slow Hamiltonian variation rate, compared to the spectral gap, is indeed sufficient to ensure adiabaticity but only when the Hamiltonian is real and nonoscillating (for instance, containing exponential or polynomial but no sinusoidal functions)
Adiabatic invariance of oscillons/I -balls
NASA Astrophysics Data System (ADS)
Kawasaki, Masahiro; Takahashi, Fuminobu; Takeda, Naoyuki
2015-11-01
Real scalar fields are known to fragment into spatially localized and long-lived solitons called oscillons or I -balls. We prove the adiabatic invariance of the oscillons/I -balls for a potential that allows periodic motion even in the presence of non-negligible spatial gradient energy. We show that such a potential is uniquely determined to be the quadratic one with a logarithmic correction, for which the oscillons/I -balls are absolutely stable. For slightly different forms of the scalar potential dominated by the quadratic one, the oscillons/I -balls are only quasistable, because the adiabatic charge is only approximately conserved. We check the conservation of the adiabatic charge of the I -balls in numerical simulation by slowly varying the coefficient of logarithmic corrections. This unambiguously shows that the longevity of oscillons/I -balls is due to the adiabatic invariance.
NASA Astrophysics Data System (ADS)
Yarkony, David
2015-03-01
The construction of fit single state potential energy surfaces (PESs), analytic representations of ab initio electronic energies and energy gradients, is now well established. These single state PESs, which are essential for accurate quantum dynamics and have found wide application in more approximate quasi-classical treatments, have revolutionized adiabatic dynamics. The situation for nonadiabatic processes involving dissociative and large amplitude motion is less sanguine. In these cases, compared to single electronic state dynamics, both the electronic structure data and the representation are more challenging to determine. We describe the recent development and applications of algorithms that enable description of multiple adiabatic electronic potential energy surfaces coupled by conical intersections in their full dimensionality using coupled quasi-diabatic states. These representations are demonstrably quasi-diabatic, provide accurate representations of conical intersection seams and can smooth out the discontinuities in electronic structure energies due to changing active orbital spaces that routinely afflict global multistate representations.
Symmetry of the Adiabatic Condition in the Piston Problem
ERIC Educational Resources Information Center
Anacleto, Joaquim; Ferreira, J. M.
2011-01-01
This study addresses a controversial issue in the adiabatic piston problem, namely that of the piston being adiabatic when it is fixed but no longer so when it can move freely. It is shown that this apparent contradiction arises from the usual definition of adiabatic condition. The issue is addressed here by requiring the adiabatic condition to be…
Development of the Concise Data Processing Assessment
ERIC Educational Resources Information Center
Day, James; Bonn, Doug
2011-01-01
The Concise Data Processing Assessment (CDPA) was developed to probe student abilities related to the nature of measurement and uncertainty and to handling data. The diagnostic is a ten question, multiple-choice test that can be used as both a pre-test and post-test. A key component of the development process was interviews with students, which…
Development Process for Science Operation Software
NASA Astrophysics Data System (ADS)
Ballester, Pascal
2015-12-01
Scientific software development at ESO involves defined processes for the main phases of project inception, monitoring of development performed by instrument consortia, application maintenance, and application support. We discuss the lessons learnt and evolution of the process for the next generation of tools and observing facilities.
ASRM test report: Autoclave cure process development
NASA Technical Reports Server (NTRS)
Nachbar, D. L.; Mitchell, Suzanne
1992-01-01
ASRM insulated segments will be autoclave cured following insulation pre-form installation and strip wind operations. Following competitive bidding, Aerojet ASRM Division (AAD) Purchase Order 100142 was awarded to American Fuel Cell and Coated Fabrics Company, Inc. (Amfuel), Magnolia, AR, for subcontracted insulation autoclave cure process development. Autoclave cure process development test requirements were included in Task 3 of TM05514, Manufacturing Process Development Specification for Integrated Insulation Characterization and Stripwind Process Development. The test objective was to establish autoclave cure process parameters for ASRM insulated segments. Six tasks were completed to: (1) evaluate cure parameters that control acceptable vulcanization of ASRM Kevlar-filled EPDM insulation material; (2) identify first and second order impact parameters on the autoclave cure process; and (3) evaluate insulation material flow-out characteristics to support pre-form configuration design.
Microscopic expression for heat in the adiabatic basis.
Polkovnikov, Anatoli
2008-11-28
We derive a microscopic expression for the instantaneous diagonal elements of the density matrix rho(nn)(t) in the adiabatic basis for an arbitrary time-dependent process in a closed Hamiltonian system. If the initial density matrix is stationary (diagonal) then this expression contains only squares of absolute values of matrix elements of the evolution operator, which can be interpreted as transition probabilities. We then derive the microscopic expression for the heat defined as the energy generated due to transitions between instantaneous energy levels. If the initial density matrix is passive [diagonal with rho(nn)(0) monotonically decreasing with energy] then the heat is non-negative in agreement with basic expectations of thermodynamics. Our findings also can be used for systematic expansion of various observables around the adiabatic limit. PMID:19113464
Fastest Effectively Adiabatic Transitions for a Collection of Harmonic Oscillators.
Boldt, Frank; Salamon, Peter; Hoffmann, Karl Heinz
2016-05-19
We discuss fastest effectively adiabatic transitions (FEATs) for a collection of noninteracting harmonic oscillators with shared controllable real frequencies. The construction of such transitions is presented for given initial and final equilibrium states, and the dependence of the minimum time control on the interval of achievable frequencies is discussed. While the FEAT times and associated FEAT processes are important in their own right as optimal controls, the FEAT time is an added feature which provides a measure of the quality of a shortcut to adiabaticity (STA). The FEAT time is evaluated for a previously reported experiment, wherein a cloud of Rb atoms is cooled following a STA recipe that took about twice as long as the FEAT speed limit, a time efficiency of 50%. PMID:26811863
Adiabatic tapered optical fiber fabrication in two step etching
NASA Astrophysics Data System (ADS)
Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.
2016-01-01
A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.
The adiabatic motion of charged dust grains in rotating magnetospheres
NASA Astrophysics Data System (ADS)
Northrop, T. G.; Hill, J. R.
1983-01-01
Adiabatic equations of motion are derived for the micrometer-sized dust grains detected in the Jovian and Saturn magnetospheres by the Pioneer 10 and 11 spacecraft. The adiabatic theory of charged particle motion is extended to the case of variable grain charge. Attention is focused on the innermost and outermost limits to the grain orbit evolution, with all orbits tending to become circular with time. The parameters such as the center equation of motion, the drift velocity, and the parallel equation of motion are obtained for grains in a rotating magnetosphere. Consideration is given to the effects of periodic grain charge-discharge, which are affected by the ambient plasma properties and the grain plasma velocity. The charge-discharge process at the gyrofrequency is determined to eliminate the invariance of the magnetic moment and cause the grain to exhibit radial movement. The magnetic moment increases or decreases as a function of the gyrophase of the charge variation.
Adiabatic creation of atomic squeezing in dark states versus decoherences
Gong, Z. R.; Sun, C. P.; Wang Xiaoguang
2010-07-15
We study the multipartite correlations of the multiatom dark states, which are characterized by the atomic squeezing beyond the pairwise entanglement. It is shown that, in the photon storage process with atomic ensemble via the electromagnetically induced transparency (EIT) mechanism, the atomic squeezing and the pairwise entanglement can be created by adiabatically manipulating the Rabi frequency of the classical light field on the atomic ensemble. We also consider the sudden death for the atomic squeezing and the pairwise entanglement under various decoherence channels. An optimal time for generating the greatest atomic squeezing and pairwise entanglement is obtained by studying in detail the competition between the adiabatic creation of quantum correlation in the atomic ensemble and the decoherence that we describe with three typical decoherence channels.
EUV mask process specifics and development challenges
NASA Astrophysics Data System (ADS)
Nesladek, Pavel
2014-07-01
EUV lithography is currently the favorite and most promising candidate among the next generation lithography (NGL) technologies. Decade ago the NGL was supposed to be used for 45 nm technology node. Due to introduction of immersion 193nm lithography, double/triple patterning and further techniques, the 193 nm lithography capabilities was greatly improved, so it is expected to be used successfully depending on business decision of the end user down to 10 nm logic. Subsequent technology node will require EUV or DSA alternative technology. Manufacturing and especially process development for EUV technology requires significant number of unique processes, in several cases performed at dedicated tools. Currently several of these tools as e.g. EUV AIMS or actinic reflectometer are not available on site yet. The process development is done using external services /tools with impact on the single unit process development timeline and the uncertainty of the process performance estimation, therefore compromises in process development, caused by assumption about similarities between optical and EUV mask made in experiment planning and omitting of tests are further reasons for challenges to unit process development. Increased defect risk and uncertainty in process qualification are just two examples, which can impact mask quality / process development. The aim of this paper is to identify critical aspects of the EUV mask manufacturing with respect to defects on the mask with focus on mask cleaning and defect repair and discuss the impact of the EUV specific requirements on the experiments needed.
Digital processing system for developing countries
NASA Technical Reports Server (NTRS)
Nanayakkara, C.; Wagner, H.
1977-01-01
An effort was undertaken to perform simple digital processing tasks using pre-existing general purpose digital computers. An experimental software package, LIGMALS, was obtained and modified for this purpose. The resulting software permits basic processing tasks to be performed including level slicing, gray mapping and ratio processing. The experience gained in this project indicates a possible direction which may be used by other developing countries to obtain digital processing capabilities.
Decoherence in current induced forces: Application to adiabatic quantum motors
NASA Astrophysics Data System (ADS)
Fernández-Alcázar, Lucas J.; Bustos-Marún, Raúl A.; Pastawski, Horacio M.
2015-08-01
Current induced forces are not only related with the discrete nature of electrons but also with its quantum character. It is natural then to wonder about the effect of decoherence. Here, we develop the theory of current induced forces including dephasing processes and we apply it to study adiabatic quantum motors (AQMs). The theory is based on Büttiker's fictitious probe model, which here is reformulated for this particular case. We prove that it accomplishes the fluctuation-dissipation theorem. We also show that, in spite of decoherence, the total work performed by the current induced forces remains equal to the pumped charge per cycle times the voltage. We find that decoherence affects not only the current induced forces of the system but also its intrinsic friction and noise, modifying in a nontrivial way the efficiency of AQMs. We apply the theory to study an AQM inspired by a classical peristaltic pump where we surprisingly find that decoherence can play a crucial role by triggering its operation. Our results can help to understand how environmentally induced dephasing affects the quantum behavior of nanomechanical devices.
Piezoelectric control of the mobility of a domain wall driven by adiabatic and non-adiabatic torques
NASA Astrophysics Data System (ADS)
de Ranieri, E.; Roy, P. E.; Fang, D.; Vehsthedt, E. K.; Irvine, A. C.; Heiss, D.; Casiraghi, A.; Campion, R. P.; Gallagher, B. L.; Jungwirth, T.; Wunderlich, J.
2013-09-01
The rich internal degrees of freedom of magnetic domain walls make them an attractive complement to electron charge for exploring new concepts of storage, transport and processing of information. Here we use the tunable internal structure of a domain wall in a perpendicularly magnetized GaMnAsP/GaAs ferromagnetic semiconductor and demonstrate devices in which piezoelectrically controlled magnetic anisotropy yields up to 500% mobility variations for an electrical-current-driven domain wall. We observe current-induced domain wall motion over a wide range of current-pulse amplitudes and report a direct observation and the piezoelectric control of the Walker breakdown separating two regimes with different mobilities. Our work demonstrates that in spin-orbit-coupled ferromagnets with weak extrinsic domain wall pinning, the piezoelectric control allows one to experimentally assess the upper and lower boundaries of the characteristic ratio of adiabatic and non-adiabatic spin-transfer torques in the current-driven domain wall motion.
Steam bottoming cycle for an adiabatic diesel engine
NASA Technical Reports Server (NTRS)
Poulin, E.; Demier, R.; Krepchin, I.; Walker, D.
1984-01-01
Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated.
Robot development for nuclear material processing
Pedrotti, L.R.; Armantrout, G.A.; Allen, D.C.; Sievers, R.H. Sr.
1991-07-01
The Department of Energy is seeking to modernize its special nuclear material (SNM) production facilities and concurrently reduce radiation exposures and process and incidental radioactive waste generated. As part of this program, Lawrence Livermore National Laboratory (LLNL) lead team is developing and adapting generic and specific applications of commercial robotic technologies to SNM pyrochemical processing and other operations. A working gantry robot within a sealed processing glove box and a telerobot control test bed are manifestations of this effort. This paper describes the development challenges and progress in adapting processing, robotic, and nuclear safety technologies to the application. 3 figs.
Development of the selective coagulation process
Yoon, R.H.; Luttrell, G.H.
1991-01-01
The aim of this project is to develop an economical method for producing low-sulfur and low-ash coals using the selective hydrophobic coagulation (SHC) process. This work has been divided into three tasks: (1) project planning and sample acquisition; (2) studies of the fundamental mechanism(s) of the selective coagulation process and the parameters that affect the process of separating coal from both the ash-forming minerals and pyritic sulfur; and (3) bench-scale process development test work to establish the best possible method(s) of separating the hydrophobic and coagula from the dispersed mineral matter.
Adiabatic Quantum Computation with Neutral Atoms
NASA Astrophysics Data System (ADS)
Biedermann, Grant
2013-03-01
We are implementing a new platform for adiabatic quantum computation (AQC)[2] based on trapped neutral atoms whose coupling is mediated by the dipole-dipole interactions of Rydberg states. Ground state cesium atoms are dressed by laser fields in a manner conditional on the Rydberg blockade mechanism,[3,4] thereby providing the requisite entangling interactions. As a benchmark we study a Quadratic Unconstrained Binary Optimization (QUBO) problem whose solution is found in the ground state spin configuration of an Ising-like model. In collaboration with Lambert Parazzoli, Sandia National Laboratories; Aaron Hankin, Center for Quantum Information and Control (CQuIC), University of New Mexico; James Chin-Wen Chou, Yuan-Yu Jau, Peter Schwindt, Cort Johnson, and George Burns, Sandia National Laboratories; Tyler Keating, Krittika Goyal, and Ivan Deutsch, Center for Quantum Information and Control (CQuIC), University of New Mexico; and Andrew Landahl, Sandia National Laboratories. This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories
Accurate adiabatic correction in the hydrogen molecule
Pachucki, Krzysztof; Komasa, Jacek
2014-12-14
A new formalism for the accurate treatment of adiabatic effects in the hydrogen molecule is presented, in which the electronic wave function is expanded in the James-Coolidge basis functions. Systematic increase in the size of the basis set permits estimation of the accuracy. Numerical results for the adiabatic correction to the Born-Oppenheimer interaction energy reveal a relative precision of 10{sup −12} at an arbitrary internuclear distance. Such calculations have been performed for 88 internuclear distances in the range of 0 < R ⩽ 12 bohrs to construct the adiabatic correction potential and to solve the nuclear Schrödinger equation. Finally, the adiabatic correction to the dissociation energies of all rovibrational levels in H{sub 2}, HD, HT, D{sub 2}, DT, and T{sub 2} has been determined. For the ground state of H{sub 2} the estimated precision is 3 × 10{sup −7} cm{sup −1}, which is almost three orders of magnitude higher than that of the best previous result. The achieved accuracy removes the adiabatic contribution from the overall error budget of the present day theoretical predictions for the rovibrational levels.
Accurate adiabatic correction in the hydrogen molecule
NASA Astrophysics Data System (ADS)
Pachucki, Krzysztof; Komasa, Jacek
2014-12-01
A new formalism for the accurate treatment of adiabatic effects in the hydrogen molecule is presented, in which the electronic wave function is expanded in the James-Coolidge basis functions. Systematic increase in the size of the basis set permits estimation of the accuracy. Numerical results for the adiabatic correction to the Born-Oppenheimer interaction energy reveal a relative precision of 10-12 at an arbitrary internuclear distance. Such calculations have been performed for 88 internuclear distances in the range of 0 < R ⩽ 12 bohrs to construct the adiabatic correction potential and to solve the nuclear Schrödinger equation. Finally, the adiabatic correction to the dissociation energies of all rovibrational levels in H2, HD, HT, D2, DT, and T2 has been determined. For the ground state of H2 the estimated precision is 3 × 10-7 cm-1, which is almost three orders of magnitude higher than that of the best previous result. The achieved accuracy removes the adiabatic contribution from the overall error budget of the present day theoretical predictions for the rovibrational levels.
Software Model Of Software-Development Process
NASA Technical Reports Server (NTRS)
Lin, Chi Y.; Synott, Debra J.; Levary, Reuven R.
1990-01-01
Collection of computer programs constitutes software tool for simulation of medium- to large-scale software-development projects. Necessary to include easily identifiable and more-readily quantifiable characteristics like costs, times, and numbers of errors. Mathematical model incorporating these and other factors of dynamics of software-development process implemented in the Software Life Cycle Simulator (SLICS) computer program. Simulates dynamics of software-development process. In combination with input and output expert software systems and knowledge-based management software system, develops information for use in managing large software-development project. Intended to aid managers in planning, managing, and controlling software-development processes by reducing uncertainties in budgets, required personnel, and schedules.
NMR implementation of adiabatic SAT algorithm using strongly modulated pulses.
Mitra, Avik; Mahesh, T S; Kumar, Anil
2008-03-28
NMR implementation of adiabatic algorithms face severe problems in homonuclear spin systems since the qubit selective pulses are long and during this period, evolution under the Hamiltonian and decoherence cause errors. The decoherence destroys the answer as it causes the final state to evolve to mixed state and in homonuclear systems, evolution under the internal Hamiltonian causes phase errors preventing the initial state to converge to the solution state. The resolution of these issues is necessary before one can proceed to implement an adiabatic algorithm in a large system where homonuclear coupled spins will become a necessity. In the present work, we demonstrate that by using "strongly modulated pulses" (SMPs) for the creation of interpolating Hamiltonian, one can circumvent both the problems and successfully implement the adiabatic SAT algorithm in a homonuclear three qubit system. This work also demonstrates that the SMPs tremendously reduce the time taken for the implementation of the algorithm, can overcome problems associated with decoherence, and will be the modality in future implementation of quantum information processing by NMR. PMID:18376911
NMR implementation of adiabatic SAT algorithm using strongly modulated pulses
NASA Astrophysics Data System (ADS)
Mitra, Avik; Mahesh, T. S.; Kumar, Anil
2008-03-01
NMR implementation of adiabatic algorithms face severe problems in homonuclear spin systems since the qubit selective pulses are long and during this period, evolution under the Hamiltonian and decoherence cause errors. The decoherence destroys the answer as it causes the final state to evolve to mixed state and in homonuclear systems, evolution under the internal Hamiltonian causes phase errors preventing the initial state to converge to the solution state. The resolution of these issues is necessary before one can proceed to implement an adiabatic algorithm in a large system where homonuclear coupled spins will become a necessity. In the present work, we demonstrate that by using "strongly modulated pulses" (SMPs) for the creation of interpolating Hamiltonian, one can circumvent both the problems and successfully implement the adiabatic SAT algorithm in a homonuclear three qubit system. This work also demonstrates that the SMPs tremendously reduce the time taken for the implementation of the algorithm, can overcome problems associated with decoherence, and will be the modality in future implementation of quantum information processing by NMR.
EUV extendibility via dry development rinse process
NASA Astrophysics Data System (ADS)
Sayan, Safak; Zheng, Tao; De Simone, Danilo; Vandenberghe, Geert
2016-03-01
Conventional photoresist processing involves resist coating, exposure, post-exposure bake, development, rinse and spin drying of a wafer. DDRP mitigates pattern collapse by applying a special polymer material (DDRM) which replaces the exposed/developed part of the photoresist material before wafer is spin dried. As noted above, the main mechanism of pattern collapse is the capillary forces governed by surface tension of rinse water and its asymmetrical recession from both sides of the lines during the drying step of the develop process. DDRP essentially eliminates these failure mechanisms by replacing remaining rinse water with DDRM and providing a structural framework that support resist lines from both sides during spin dry process. Dry development rinse process (DDRP) eliminates the root causes responsible for pattern collapse of photoresist line structures. Since these collapse mechanisms are mitigated, without the need for changes in the photoresist itself, achievable resolution of the state-of-the-art EUV photoresists can further be improved.
WRAP process area development control work plan
Leist, K.L., Fluor Daniel Hanford
1997-02-27
This work plan defines the manner in which the Waste Receiving and Processing Facility, Module I Process Area will be maintained under development control status. This status permits resolution of identified design discrepancies, control system changes, as-building of equipment, and perform modifications to increase process operability and maintainability as parallel efforts. This work plan maintains configuration control as these efforts are undertaken. This task will end with system testing and reissue of field verified design drawings.
Course Development: Industrial or Social Process.
ERIC Educational Resources Information Center
Kaufman, David
The development of course materials at the Open Learning Institute, British Columbia, Canada, is examined from two perspectives: as an industrial process and as a social process. The public institute provides distance education through paced home-study courses. The course team model used at the Institute is a system approach. Course development…
Teaching Information Systems Development via Process Variants
ERIC Educational Resources Information Center
Tan, Wee-Kek; Tan, Chuan-Hoo
2010-01-01
Acquiring the knowledge to assemble an integrated Information System (IS) development process that is tailored to the specific needs of a project has become increasingly important. It is therefore necessary for educators to impart to students this crucial skill. However, Situational Method Engineering (SME) is an inherently complex process that…
A Comprehensive Process for Display Systems Development.
ERIC Educational Resources Information Center
Simcox, William A.
A comprehensive development process for display design, focusing on computer-generated cathode ray tube (CRT) displays is presented. A framework is created for breaking the display into its component parts, used to guide the design process. The objective is to design or select the most cost effective graphics solution (hardware and software) to…
Precision grinding process development for brittle materials
Blaedel, K L; Davis, P J; Piscotty, M A
1999-04-01
High performance, brittle materials are the materials of choice for many of today's engineering applications. This paper describes three separate precision grinding processes developed at Lawrence Liver-more National Laboratory to machine precision ceramic components. Included in the discussion of the precision processes is a variety of grinding wheel dressing, truing and profiling techniques.
Nonadiabatic exchange dynamics during adiabatic frequency sweeps
NASA Astrophysics Data System (ADS)
Barbara, Thomas M.
2016-04-01
A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging.
Extensive Adiabatic Invariants for Nonlinear Chains
NASA Astrophysics Data System (ADS)
Giorgilli, Antonio; Paleari, Simone; Penati, Tiziano
2012-09-01
We look for extensive adiabatic invariants in nonlinear chains in the thermodynamic limit. Considering the quadratic part of the Klein-Gordon Hamiltonian, by a linear change of variables we transform it into a sum of two parts in involution. At variance with the usual method of introducing normal modes, our constructive procedure allows us to exploit the complete resonance, while keeping the extensive nature of the system. Next we construct a nonlinear approximation of an extensive adiabatic invariant for a perturbation of the discrete nonlinear Schrödinger model. The fluctuations of this quantity are controlled via Gibbs measure estimates independent of the system size, for a large set of initial data at low specific energy. Finally, by numerical calculations we show that our adiabatic invariant is well conserved for times much longer than predicted by our first order theory, with fluctuation much smaller than expected according to standard statistical estimates.
Anderson localization makes adiabatic quantum optimization fail
Altshuler, Boris; Krovi, Hari; Roland, Jérémie
2010-01-01
Understanding NP-complete problems is a central topic in computer science (NP stands for nondeterministic polynomial time). This is why adiabatic quantum optimization has attracted so much attention, as it provided a new approach to tackle NP-complete problems using a quantum computer. The efficiency of this approach is limited by small spectral gaps between the ground and excited states of the quantum computer’s Hamiltonian. We show that the statistics of the gaps can be analyzed in a novel way, borrowed from the study of quantum disordered systems in statistical mechanics. It turns out that due to a phenomenon similar to Anderson localization, exponentially small gaps appear close to the end of the adiabatic algorithm for large random instances of NP-complete problems. This implies that unfortunately, adiabatic quantum optimization fails: The system gets trapped in one of the numerous local minima. PMID:20616043
Dynamics of Quantum Adiabatic Evolution Algorithm for Number Partitioning
NASA Technical Reports Server (NTRS)
Smelyanskiy, V. N.; Toussaint, U. V.; Timucin, D. A.
2002-01-01
We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size n. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxiliary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum excitation gap. g min, = O(n 2(exp -n/2), corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simultaneous flipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to 'the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimensional quantum diffusion in the energy space. This effect provides a general limitation of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.
Steam bottoming cycle for an adiabatic diesel engine
Poulin, E.; Demler, R.; Krepchin, I.; Walker, D.
1984-03-01
A study of steam bottoming cycles using adiabatic diesel engine exhaust heat projected substantial performance and economic benefits for long haul trucks. A parametric analysis of steam cycle and system component variables, system cost, size and performance was conducted. An 811 K/6.90 MPa state-of-the-art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. When applied to a NASA specified turbo-charged adiabatic diesel the bottoming system increased the diesel output by almost 18%. In a comparison of the costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with after-cooling with the same total output, the annual fuel savings less the added maintenance cost was determined to cover the increased initial cost of the TC/B system in a payback period of 2.3 years. Also during this program steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability were considered and the cost and performance of advanced systems were evaluated.
Dynamics of Quantum Adiabatic Evolution Algorithm for Number Partitioning
NASA Technical Reports Server (NTRS)
Smelyanskiy, Vadius; vonToussaint, Udo V.; Timucin, Dogan A.; Clancy, Daniel (Technical Monitor)
2002-01-01
We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size n. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxiliary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum exitation gap, gmin = O(n2(sup -n/2)), corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simultaneous flipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimensional quantum diffusion in the energy space. This effect provides a general limitation of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.
Applications and error correction for adiabatic quantum optimization
NASA Astrophysics Data System (ADS)
Pudenz, Kristen
Adiabatic quantum optimization (AQO) is a fast-developing subfield of quantum information processing which holds great promise in the relatively near future. Here we develop an application, quantum anomaly detection, and an error correction code, Quantum Annealing Correction (QAC), for use with AQO. The motivation for the anomaly detection algorithm is the problematic nature of classical software verification and validation (V&V). The number of lines of code written for safety-critical applications such as cars and aircraft increases each year, and with it the cost of finding errors grows exponentially (the cost of overlooking errors, which can be measured in human safety, is arguably even higher). We approach the V&V problem by using a quantum machine learning algorithm to identify charateristics of software operations that are implemented outside of specifications, then define an AQO to return these anomalous operations as its result. Our error correction work is the first large-scale experimental demonstration of quantum error correcting codes. We develop QAC and apply it to USC's equipment, the first and second generation of commercially available D-Wave AQO processors. We first show comprehensive experimental results for the code's performance on antiferromagnetic chains, scaling the problem size up to 86 logical qubits (344 physical qubits) and recovering significant encoded success rates even when the unencoded success rates drop to almost nothing. A broader set of randomized benchmarking problems is then introduced, for which we observe similar behavior to the antiferromagnetic chain, specifically that the use of QAC is almost always advantageous for problems of sufficient size and difficulty. Along the way, we develop problem-specific optimizations for the code and gain insight into the various on-chip error mechanisms (most prominently thermal noise, since the hardware operates at finite temperature) and the ways QAC counteracts them. We finish by showing
Process-Based Quality (PBQ) Tools Development
Cummins, J.L.
2001-12-03
The objective of this effort is to benchmark the development of process-based quality tools for application in CAD (computer-aided design) model-based applications. The processes of interest are design, manufacturing, and quality process applications. A study was commissioned addressing the impact, current technologies, and known problem areas in application of 3D MCAD (3-dimensional mechanical computer-aided design) models and model integrity on downstream manufacturing and quality processes. The downstream manufacturing and product quality processes are profoundly influenced and dependent on model quality and modeling process integrity. The goal is to illustrate and expedite the modeling and downstream model-based technologies for available or conceptual methods and tools to achieve maximum economic advantage and advance process-based quality concepts.
The message processing and distribution system development
NASA Astrophysics Data System (ADS)
Whitten, K. L.
1981-06-01
A historical approach is used in presenting the life cycle development of the Navy's message processing and distribution system beginning with the planning phase and ending with the integrated logistic support phase. Several maintenance problems which occurred after the system was accepted for fleet use were examined to determine if they resulted from errors in the acquisition process. The critical decision points of the acquisition process are examined and constructive recommendations are made for avoiding the problems which hindered the successful development of this system.
Stimulated Raman adiabatic passage in Tm{sup 3+}:YAG
Alexander, A. L.; Lauro, R.; Louchet, A.; Chaneliere, T.; Le Goueet, J. L.
2008-10-01
We report on the experimental demonstration of stimulated Raman adiabatic passage in a Tm{sup 3+}:YAG crystal. Tm{sup 3+}:YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm{sup 3+}:YAG system are presented along with the corresponding experimental results.
ASRM process development in aqueous cleaning
NASA Technical Reports Server (NTRS)
Swisher, Bill
1992-01-01
Viewgraphs are included on process development in aqueous cleaning which is taking place at the Aerojet Advanced Solid Rocket Motor (ASRM) Division under a NASA Marshall Space and Flight Center contract for design, development, test, and evaluation of the ASRM including new production facilities. The ASRM will utilize aqueous cleaning in several manufacturing process steps to clean case segments, nozzle metal components, and igniter closures. ASRM manufacturing process development is underway, including agent selection, agent characterization, subscale process optimization, bonding verification, and scale-up validation. Process parameters are currently being tested for optimization utilizing a Taguci Matrix, including agent concentration, cleaning solution temperature, agitation and immersion time, rinse water amount and temperature, and use/non-use of drying air. Based on results of process development testing to date, several observations are offered: aqueous cleaning appears effective for steels and SermeTel-coated metals in ASRM processing; aqueous cleaning agents may stain and/or attack bare aluminum metals to various extents; aqueous cleaning appears unsuitable for thermal sprayed aluminum-coated steel; aqueous cleaning appears to adequately remove a wide range of contaminants from flat metal surfaces, but supplementary assistance may be needed to remove clumps of tenacious contaminants embedded in holes, etc.; and hot rinse water appears to be beneficial to aid in drying of bare steel and retarding oxidation rate.
ASRM process development in aqueous cleaning
NASA Astrophysics Data System (ADS)
Swisher, Bill
1992-12-01
Viewgraphs are included on process development in aqueous cleaning which is taking place at the Aerojet Advanced Solid Rocket Motor (ASRM) Division under a NASA Marshall Space and Flight Center contract for design, development, test, and evaluation of the ASRM including new production facilities. The ASRM will utilize aqueous cleaning in several manufacturing process steps to clean case segments, nozzle metal components, and igniter closures. ASRM manufacturing process development is underway, including agent selection, agent characterization, subscale process optimization, bonding verification, and scale-up validation. Process parameters are currently being tested for optimization utilizing a Taguci Matrix, including agent concentration, cleaning solution temperature, agitation and immersion time, rinse water amount and temperature, and use/non-use of drying air. Based on results of process development testing to date, several observations are offered: aqueous cleaning appears effective for steels and SermeTel-coated metals in ASRM processing; aqueous cleaning agents may stain and/or attack bare aluminum metals to various extents; aqueous cleaning appears unsuitable for thermal sprayed aluminum-coated steel; aqueous cleaning appears to adequately remove a wide range of contaminants from flat metal surfaces, but supplementary assistance may be needed to remove clumps of tenacious contaminants embedded in holes, etc.; and hot rinse water appears to be beneficial to aid in drying of bare steel and retarding oxidation rate.
Campbell, J.A.L.; Carty, R.H.; Foster, H.
1994-05-01
The work performed during the ninth quarterly reporting period (November 21, 1993 through February 20, 1994) is presented in this report. The overall objective of this project is to develop the IGT Mid-Gasification MILDGAS) process for near-term commercialization. The specific objectives of the program are to: design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup; obtain large batches of coal-derived co-products for industrial evaluation; prepare a detailed design of a demonstration unit; and develop technical and economic plans for commercialization of the MILDGAS process. The project team that is performing the initial phases of the PDU development are: Kerr-McGee Coal Corporation (K-M Coal), the Institute of Gas Technology (IGT), Bechtel Corporation (Bechtel), and Southern Illinois University at Carbondale (SIUC). The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The 1 ton/hr PDU facility that is to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of gases, coal liquids, and char; a three-stage condensation train to condense and store the liquid products; and coal feeding and char handling equipment. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste. A Finding of No Significant Impact (FONSI) was obtained on our NEPA submittal on February 10, 1994, allowing us to proceed with the project. The permitting documentation for the authority to construct was submitted to the Illinois EPA this quarter. Work to finalize the process design and obtain updated bids on the PDU was begun after the FONSI was obtained.
Spontaneous emission in stimulated Raman adiabatic passage
Ivanov, P. A.; Vitanov, N. V.; Bergmann, K.
2005-11-15
This work explores the effect of spontaneous emission on the population transfer efficiency in stimulated Raman adiabatic passage (STIRAP). The approach uses adiabatic elimination of weakly coupled density matrix elements in the Liouville equation, from which a very accurate analytic approximation is derived. The loss of population transfer efficiency is found to decrease exponentially with the factor {omega}{sub 0}{sup 2}/{gamma}, where {gamma} is the spontaneous emission rate and {omega}{sub 0} is the peak Rabi frequency. The transfer efficiency increases with the pulse delay and reaches a steady value. For large pulse delay and large spontaneous emission rate STIRAP degenerates into optical pumping.
Adiabatic Hyperspherical Analysis of Realistic Nuclear Potentials
NASA Astrophysics Data System (ADS)
Daily, K. M.; Kievsky, Alejandro; Greene, Chris H.
2015-12-01
Using the hyperspherical adiabatic method with the realistic nuclear potentials Argonne V14, Argonne V18, and Argonne V18 with the Urbana IX three-body potential, we calculate the adiabatic potentials and the triton bound state energies. We find that a discrete variable representation with the slow variable discretization method along the hyperradial degree of freedom results in energies consistent with the literature. However, using a Laguerre basis results in missing energy, even when extrapolated to an infinite number of basis functions and channels. We do not include the isospin T = 3/2 contribution in our analysis.
On black hole spectroscopy via adiabatic invariance
NASA Astrophysics Data System (ADS)
Jiang, Qing-Quan; Han, Yan
2012-12-01
In this Letter, we obtain the black hole spectroscopy by combining the black hole property of adiabaticity and the oscillating velocity of the black hole horizon. This velocity is obtained in the tunneling framework. In particular, we declare, if requiring canonical invariance, the adiabatic invariant quantity should be of the covariant form Iadia = ∮pi dqi. Using it, the horizon area of a Schwarzschild black hole is quantized independently of the choice of coordinates, with an equally spaced spectroscopy always given by ΔA = 8 π lp2 in the Schwarzschild and Painlevé coordinates.
Complexity of the Quantum Adiabatic Algorithm
NASA Technical Reports Server (NTRS)
Hen, Itay
2013-01-01
The Quantum Adiabatic Algorithm (QAA) has been proposed as a mechanism for efficiently solving optimization problems on a quantum computer. Since adiabatic computation is analog in nature and does not require the design and use of quantum gates, it can be thought of as a simpler and perhaps more profound method for performing quantum computations that might also be easier to implement experimentally. While these features have generated substantial research in QAA, to date there is still a lack of solid evidence that the algorithm can outperform classical optimization algorithms.
Adiabatic approximation for nucleus-nucleus scattering
Johnson, R.C.
2005-10-14
Adiabatic approximations to few-body models of nuclear scattering are described with emphasis on reactions with deuterons and halo nuclei (frozen halo approximation) as projectiles. The different ways the approximation should be implemented in a consistent theory of elastic scattering, stripping and break-up are explained and the conditions for the theory's validity are briefly discussed. A formalism which links few-body models and the underlying many-body system is outlined and the connection between the adiabatic and CDCC methods is reviewed.
Using Reflection to Develop Higher Order Processes
ERIC Educational Resources Information Center
Lerch, Carol; Bilics, Andrea; Colley, Binta
2006-01-01
The main purpose of this study was to look at how we used specific writing assignments in our courses to encourage metacognitive reflection in order to increase the learning that takes place. The study also aimed to aid in the development of higher order processing skills through the development of student reflection. The students involved in the…
Information Processing Theory and Conceptual Development.
ERIC Educational Resources Information Center
Schroder, H. M.
An educational program based upon information processing theory has been developed at Southern Illinois University. The integrating theme was the development of conceptual ability for coping with social and personal problems. It utilized student information search and concept formation as foundations for discussion and judgment and was organized…
The Cassini-Huygens Sequence Development Process
NASA Technical Reports Server (NTRS)
Long, Jennifer H.; Heventhal, William M., III; Javidnia, Shahram
2006-01-01
Each phase of the sequence development process had to overcome many operational challenges due to the immense complexity of the spacecraft, tour design, pointing capabilities, flight rules and software development. This paper will address the specific challenges related to each of those complexities and the methods used to overcome them during operation.
Cognitive Process of Development in Children
ERIC Educational Resources Information Center
Boddington, Eulalee N.
2009-01-01
In this article we explored the theories of Arnold Gesell, Erik Erickson and Jean Piaget about how human beings development. In this component we will analyze the cognitive processes of how children perceive and develop, in particular children from a cross-cultural background. How learning takes place, and how the influences of culture, and…
Preform Characterization in VARTM Process Model Development
NASA Technical Reports Server (NTRS)
Grimsley, Brian W.; Cano, Roberto J.; Hubert, Pascal; Loos, Alfred C.; Kellen, Charles B.; Jensen, Brian J.
2004-01-01
Vacuum-Assisted Resin Transfer Molding (VARTM) is a Liquid Composite Molding (LCM) process where both resin injection and fiber compaction are achieved under pressures of 101.3 kPa or less. Originally developed over a decade ago for marine composite fabrication, VARTM is now considered a viable process for the fabrication of aerospace composites (1,2). In order to optimize and further improve the process, a finite element analysis (FEA) process model is being developed to include the coupled phenomenon of resin flow, preform compaction and resin cure. The model input parameters are obtained from resin and fiber-preform characterization tests. In this study, the compaction behavior and the Darcy permeability of a commercially available carbon fabric are characterized. The resulting empirical model equations are input to the 3- Dimensional Infiltration, version 5 (3DINFILv.5) process model to simulate infiltration of a composite panel.
Computer-aided software development process design
NASA Technical Reports Server (NTRS)
Lin, Chi Y.; Levary, Reuven R.
1989-01-01
The authors describe an intelligent tool designed to aid managers of software development projects in planning, managing, and controlling the development process of medium- to large-scale software projects. Its purpose is to reduce uncertainties in the budget, personnel, and schedule planning of software development projects. It is based on dynamic model for the software development and maintenance life-cycle process. This dynamic process is composed of a number of time-varying, interacting developmental phases, each characterized by its intended functions and requirements. System dynamics is used as a modeling methodology. The resulting Software LIfe-Cycle Simulator (SLICS) and the hybrid expert simulation system of which it is a subsystem are described.
Adult Personality Development: Dynamics and Processes
Diehl, Manfred; Hooker, Karen
2013-01-01
The focus of this special issue of Research in Human Development is on adult personality and how personality may contribute to and be involved in adult development. Specifically, the contributions in this issue focus on the links between personality structures (e.g., traits) and personality processes (e.g., goal pursuit, self--regulation) and emphasize the contributions that intensive repeated measurement approaches can make to the understanding of personality and development across the adult life span. PMID:24068889
Doane, E.P.; Carty, R.H.; Foster, H.
1995-03-01
The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup; obtain large batches of coal-derived co-products for industrial evaluation; prepare a detailed design of a demonstration unit; develop technical and economic plans for commercialization of the MILDGAS process. The project team that is performing the initial phases of the PDU development are: Kerr-McGee Coal Corporation (K-M Coal), the Institute of Gas Technology (IGT), Bechtel Corporation (Bechtel), and Southern Illinois University at Carbondale (SIUC). The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300{degrees}F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The 1 ton/hr PDU facility that is to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of gases, coal liquids, and char; a three-stage condensation train to condense and store the liquid products; and coal feeding and char handling equipment. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste. This quarter, Roberts and Schaefer (R&S) of Salt Lake City, Utah was awarded the contract to perform the detailed design for the gasification, liquids recovery and overall plant design coordination. They began work in December of 1994 and a meeting was held between R&S, Bechtel, and IGT to discuss control methods, detailed equipment design, the heavy liquids filter, and possible modifications to the first and second stage cyclones.
Adiabatic Compression in a Fire Syringe.
ERIC Educational Resources Information Center
Hayn, Carl H.; Baird, Scott C.
1985-01-01
Suggests using better materials in fire syringes to obtain more effective results during demonstrations which show the elevation in temperature upon a very rapid (adiabatic) compression of air. Also describes an experiment (using ignition temperatures) which introduces students to the use of thermocouples for high temperature measurements. (DH)
Characterization of adiabatic shear bands in AM60B magnesium alloy under ballistic impact
Zou, D.L.; Zhen, L. Xu, C.Y.; Shao, W.Z.
2011-05-15
Adiabatic shear bands in Mg alloy under ballistic impact at a velocity of 0.5 km.s{sup -1} were characterized by means of optical microscope, scanning electron microscope, transmission electron microscope and indenter technique. The results show that adiabatic shear bands were formed around the impacted crater, and the deformed and transformed bands were distinguished by etching colors in metallographic observation. TEM observation shows that the deformed bands were composed of the elongated grains and high density dislocations, while the transformed bands composed of the ultrafine and equiaxed grains were confirmed. In initial stage, the severe localized plastic deformation led to the formation of elongated grains in the deformed bands. With localized strain increasing, the severe localized deformation assisted with the plastic temperature rising led to the severe deformation grains evolved into the ultrafine and equiaxed grains, while the deformed bands were developed into transformed bands. The formation of the ultrafine and equiaxed grains in the transformed bands should be attributed to the twinning-induced rotational dynamic recrystallization mechanism. High microhardness in the bands was obtained because of the strain hardening, grain refining and content concentration. - Research Highlights: {yields} Deformed and transformed bands are found in Mg alloy under ballistic impact. {yields} The microstructures in the deformed and transformed bands are characterized. {yields} The evolution process of the microstructure in the bands is discussed.
Development of modified FT (MFT) process
Jinglai Zhou; Zhixin Zhang; Wenjie Shen
1995-12-31
Two-Stage Modified FT (MFT) process has been developed for producing high-octane gasoline from coal-based syngas. The main R&D are focused on the development of catalysts and technologies process. Duration tests were finished in the single-tube reactor, pilot plant (100T/Y), and industrial demonstration plant (2000T/Y). A series of satisfactory results has been obtained in terms of operating reliability of equipments, performance of catalysts, purification of coal - based syngas, optimum operating conditions, properties of gasoline and economics etc. Further scaling - up commercial plant is being considered.
Apoptotic processes during mammalian preimplantation development.
Fabian, Dusan; Koppel, Juraj; Maddox-Hyttel, Poul
2005-07-15
The paper provides a review of the current state of knowledge on apoptosis during normal preimplantation development based on the literature and on the authors' own findings. Information is focused on the occurrence and the characteristics of spontaneous apoptotic processes. Reports concerning the chronology and the incidence of programmed cell death in mouse, cow, pig and human embryos in early preimplantation stages up to the blastocyst stage are summarized. In addition, specific attributes of the apoptotic process in mammalian preimplantation development are provided, including the description of both morphological and biochemical features of cell death. PMID:15955348
Development of superplastic steel processing. Final report
Goldberg, A.
1995-04-01
Objective was to provide basis for producing, processing, and forming UHCS (ultrahigh carbon steel) on a commercial scale. Business plans were developed for potential commercialization. Effort was directed at improving the combination of flow stress and forming rates in UHCS alloys in order to make near net shape superplastic forming competitive; the result was the development of a series of UHCS alloys and processing, the selection of which depends on the specific requirements of the commercial application. Useful ancillary properties of these materials include: improved mechanical properties, wear resistance, and oxidation resistance at elevated temperatures.
Development of emission factors for polycarbonate processing.
Rhodes, Verne L; Kriek, George; Lazear, Nelson; Kasakevich, Jean; Martinko, Marie; Heggs, R P; Holdren, M W; Wisbith, A S; Keigley, G W; Williams, J D; Chuang, J C; Satola, J R
2002-07-01
Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations. PMID:12139342
Communication: Adiabatic and non-adiabatic electron-nuclear motion: Quantum and classical dynamics
NASA Astrophysics Data System (ADS)
Albert, Julian; Kaiser, Dustin; Engel, Volker
2016-05-01
Using a model for coupled electronic-nuclear motion we investigate the range from negligible to strong non-adiabatic coupling. In the adiabatic case, the quantum dynamics proceeds in a single electronic state, whereas for strong coupling a complete transition between two adiabatic electronic states takes place. It is shown that in all coupling regimes the short-time wave-packet dynamics can be described using ensembles of classical trajectories in the phase space spanned by electronic and nuclear degrees of freedom. We thus provide an example which documents that the quantum concept of non-adiabatic transitions is not necessarily needed if electronic and nuclear motion is treated on the same footing.
The dynamic instability of adiabatic blast waves
NASA Technical Reports Server (NTRS)
Ryu, Dongsu; Vishniac, Ethan T.
1991-01-01
Adiabatic blastwaves, which have a total energy injected from the center E varies as t(sup q) and propagate through a preshock medium with a density rho(sub E) varies as r(sup -omega) are described by a family of similarity solutions. Previous work has shown that adiabatic blastwaves with increasing or constant postshock entropy behind the shock front are susceptible to an oscillatory instability, caused by the difference between the nature of the forces on the two sides of the dense shell behind the shock front. This instability sets in if the dense postshock layer is sufficiently thin. The stability of adiabatic blastwaves with a decreasing postshock entropy is considered. Such blastwaves, if they are decelerating, always have a region behind the shock front which is subject to convection. Some accelerating blastwaves also have such region, depending on the values of q, omega, and gamma where gamma is the adiabatic index. However, since the shock interface stabilizes dynamically induced perturbations, blastwaves become convectively unstable only if the convective zone is localized around the origin or a contact discontinuity far from the shock front. On the other hand, the contact discontinuity of accelerating blastwaves is subject to a strong Rayleigh-Taylor instability. The frequency spectra of the nonradial, normal modes of adiabatic blastwaves have been calculated. The results have been applied to the shocks propagating through supernovae envelopes. It is shown that the metal/He and He/H interfaces are strongly unstable against the Rayleigh-Taylor instability. This instability will induce mixing in supernovae envelopes. In addition the implications of this work for the evolution of planetary nebulae is discussed.