479 research outputs found
Farm policy review
Farm Policy Review for the state of Mississippi, a state report compiled from input from farmers, and giving input on the various federal and state agencies that work with agriculture. Sent from C. L. Neill, chairman of the State Agricultural Mobilization Committee, to members of the State Agricultural Mobilization Committee for discussion at a October 11, 1951 meeting.https://scholarsjunction.msstate.edu/mss-stevens-papers/1072/thumbnail.jp
Entanglement and complexity of interacting qubits subject to asymmetric noise
The simulation complexity of predicting the time evolution of delocalized
many-body quantum systems has attracted much recent interest, and simulations
of such systems in real quantum hardware are promising routes to demonstrating
a quantum advantage over classical machines. In these proposals, random noise
is an obstacle that must be overcome for a faithful simulation, and a single
error event can be enough to drive the system to a classically trivial state.
We argue that this need not always be the case, and consider a modification to
a leading quantum sampling problem-- time evolution in an interacting
Bose-Hubbard chain of transmon qubits [Neill et al, Science 2018] -- where each
site in the chain has a driven coupling to a lossy resonator and particle
number is no longer conserved. The resulting quantum dynamics are complex and
highly nontrivial. We argue that this problem is harder to simulate than the
isolated chain, and that it can achieve volume-law entanglement even in the
strong noise limit, likely persisting up to system sizes beyond the scope of
classical simulation. Further, we show that the metrics which suggest classical
intractability for the isolated chain point to similar conclusions in the noisy
case. These results suggest that quantum sampling problems including nontrivial
noise could be good candidates for demonstrating a quantum advantage in
near-term hardware.Comment: 20 pages, 15 figure
Fabrication process for combustion chamber/nozzle assembly
An integral, lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its smaller end with a rocket body, and terminates at its larger end in a generally contact contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time
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A path towards quantum supremacy with superconducting qubits
A key milestone on the path towards building a quantum computer will be the demonstration of an algorithm which exceeds the capabilities of any classical computer - achieving so called quantum supremacy. The challenge in developing such an algorithm lies in balancing computational complexity with experimental feasibility, particularly in the presence of errors. In this thesis, we design superconducting qubits and algorithms with the goal of finding such a balance. We implement a wide variety of control protocols, including parametric drive, adiabatic control, floquet evolution and time-domain spectroscopy. These tools are used to the study topological invariants, quantum chaos, quantum statistical mechanics, chiral symmetry breaking and many-body localization. We present experimental techniques for characterizing the complexity and fidelity of these algorithms and show that quantum supremacy is achievable using existing technology
Comparison of the Efficacy of two Anticonvulsants, Phenytoin and Valproate to Improve PCP and d-amphetamine Induced Deficits in a Reversal Learning Task in the Rat
Recent studies in our laboratory have shown that PCP (phencyclidine) and d-amphetamine induce a cognitive deficit in rats, in a paradigm of potential relevance for the pathology of schizophrenia. Atypical, but not classical antipsychotics and the anticonvulsant, lamotrigine have been shown to prevent a selective reversal learning deficit induced by PCP. In contrast, only haloperidol reversed the d-amphetamine-induced deficit. The present study aimed to explore the ability of two anticonvulsants with differing mechanism of action, valproate and phenytoin to attenuate the cognitive deficits induced by PCP and d-amphetamine in the reversal learning paradigm. PCP at 1.5 mg/kg and d-amphetamine at 0.5 mg/kg both produced a selective and significant reduction in performance of the reversal phase with no effect on the initial phase of the task in female-hooded Lister rats. Valproate (25–200 mg/kg) and phenytoin (25–50 mg/kg) had no effect on performance when administered alone. Valproate (100–200 mg/kg), whose principle action is thought to be the enhancement of GABA transmission, was unable to prevent the cognitive deficit induced by either PCP or d-amphetamine. Conversely, phenytoin (50 mg/kg), a use-dependent sodium channel inhibitor, significantly prevented the deficit induced by PCP, but not d-amphetamine. These results add to our earlier work with lamotrigine, and suggest that sodium channel blockade may be a mechanism by which some anticonvulsant drugs can prevent the PCP-induced deficit. These data have implications for the use of anticonvulsant drugs in the treatment of cognitive or psychotic disorders
Generalized DF spaces
Bibliography: pages 102-106.A DF space is a topological vector space sharing certain essential properties with the strong duals of Frechet spaces. The class of DF spaces includes not only all such duals, but also every· normed space and many other spaces besides. The definition of a DF space is due to Grothendieck, who derived almost all the important results concerning such spaces. The "generalized DF spaces" in the title of this thesis are locally convex topological vector spaces whose topologies are determined by their restrictions to an absorbent sequence of bounded sets. In the case when this sequence is a fundamental sequence of bounded sets, we obtain the gDF spaces. Many. of the properties of DF spaces are shared by all gDF spaces
Separability and metrisability in locally convex spaces
Bibliography: pages 58-61.This thesis is devoted to a study of the relationship between separability and metrisability in the context of locally convex spaces. The duality between sep- arability and weak*-metrisability does not carry over to non-metrisable locally convex spaces; the best that can be said in this case is that the equicontinuous subsets in the dual of a separable locally convex space are weak*-metrisable. To get around this difficulty, we often prefer to use the idea of separability by seminorm: a locally convex space E is separable by seminorm if and only if the equicontinuous subsets of its dual are weak*-metrisable. On any locally convex space E there is a finest topology Tχ which is coarser than the given topology and which makes E separable by seminorm. A question that arises is under what conditions a space E is Tχ-complete. In trying to answer this question, we are led to an intriguing binary relation which G.A. Edgar originally defined on the class of Banach spaces. In the first two Chapters of this thesis, we show that many of the results in Edgar's paper can be expressed in terms of the completeness of a space with respect to various topologies
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