1,728 research outputs found
The Virgin and the Grasshoppers: Persistence and Piety in German-Catholic America
This paper examines two inter-related historical problems -- the impact of the market revolution in nineteenth-century American and the disruptive impact of immigration on community life -- by chronicling the construction of a votive chapel in the heavily German-Catholic Stearns County, Minnesota. The chapel, dedicated to the Virgin Mary, was ostensibly built to secure divine relief from a plague of Rocky Mountain locusts that was devastating the area. At the same time, the chapel and the rituals surrounding its construction spoke to other community needs and functioned in diverse ways to address other community problems. For one, the shrine spoke directly to the condition of women, who had experiences a deterioration in status as a product of migration, and modeled better treatment while simultaneously explaining the cause and meaning of their suffering. The religious procession that accompanied the chapel construction also reaffirmed traditional pre-capitalist values nad helped guide these German Catholic settlers in their engagement with new, distant commodity markets
Walden Township Historic Resource Survey
The Walden Township Historic Resource Survey\u27s aim was to conduct a model records survey of all materials relevant to the history of a single township in Pope County, Minnesota. The project produced an extensive bibliography and database to be used by township officials, genealogists and local historians
Improved Metric Distortion for Deterministic Social Choice Rules
In this paper, we study the metric distortion of deterministic social choice
rules that choose a winning candidate from a set of candidates based on voter
preferences. Voters and candidates are located in an underlying metric space. A
voter has cost equal to her distance to the winning candidate. Ordinal social
choice rules only have access to the ordinal preferences of the voters that are
assumed to be consistent with the metric distances. Our goal is to design an
ordinal social choice rule with minimum distortion, which is the worst-case
ratio, over all consistent metrics, between the social cost of the rule and
that of the optimal omniscient rule with knowledge of the underlying metric
space.
The distortion of the best deterministic social choice rule was known to be
between and . It had been conjectured that any rule that only looks at
the weighted tournament graph on the candidates cannot have distortion better
than . In our paper, we disprove it by presenting a weighted tournament rule
with distortion of . We design this rule by generalizing the classic
notion of uncovered sets, and further show that this class of rules cannot have
distortion better than . We then propose a new voting rule, via an
alternative generalization of uncovered sets. We show that if a candidate
satisfying the criterion of this voting rule exists, then choosing such a
candidate yields a distortion bound of , matching the lower bound. We
present a combinatorial conjecture that implies distortion of , and verify
it for small numbers of candidates and voters by computer experiments. Using
our framework, we also show that selecting any candidate guarantees distortion
of at most when the weighted tournament graph is cyclically symmetric.Comment: EC 201
Quantum State Tomography via Compressed Sensing
We establish methods for quantum state tomography based on compressed sensing. These methods are specialized for quantum states that are fairly pure, and they offer a significant performance improvement on large quantum systems. In particular, they are able to reconstruct an unknown density matrix of dimension d and rank r using O(rdlog^2d) measurement settings, compared to standard methods that require d^2 settings. Our methods have several features that make them amenable to experimental implementation: they require only simple Pauli measurements, use fast convex optimization, are stable against noise, and can be applied to states that are only approximately low rank. The acquired data can be used to certify that the state is indeed close to pure, so no a priori assumptions are needed
The String Calculation of QCD Wilson Loops on Arbitrary Surfaces
Compact string expressions are found for non-intersecting Wilson loops in
SU(N) Yang-Mills theory on any surface (orientable or nonorientable) as a
weighted sum over covers of the surface. All terms from the coupled chiral
sectors of the 1/N expansion of the Wilson loop expectation values are
included.Comment: 10 pages, LaTeX, no figure
Large-N Universality of the Two-Dimensional Yang-Mills String
We exhibit the gauge-group independence (``universality'') of all normalized
non-intersecting Wilson loop expectation values in the large N limit of
two-dimensional Yang-Mills theory. This universality is most easily understood
via the string theory reformulation of these gauge theories. By constructing an
isomorphism between the string maps contributing to normalized Wilson loop
expectation values in the different theories, we prove the large N universality
of these observables on any surface. The string calculation of the Wilson loop
expectation value on the sphere also leads to an indication of the large N
phase transition separating strong- and weak-coupling phases.Comment: 18 pages, phyzzx macro, no figure
Bound States of Dimensionally Reduced {SYM}_{2+1} at Finite N
We consider the dimensional reduction of N=1 {SYM}_{2+1} to 1+1 dimensions.
The gauge groups we consider are U(N) and SU(N), where N is finite. We
formulate the continuum bound state problem in the light-cone formalism, and
show that any normalizable SU(N) bound state must be a superposition of an
infinite number of Fock states. We also discuss how massless states arise in
the DLCQ formulation for certain discretizations.Comment: 14 pages, REVTE
The monomial representations of the Clifford group
We show that the Clifford group - the normaliser of the Weyl-Heisenberg group
- can be represented by monomial phase-permutation matrices if and only if the
dimension is a square number. This simplifies expressions for SIC vectors, and
has other applications to SICs and to Mutually Unbiased Bases. Exact solutions
for SICs in dimension 16 are presented for the first time.Comment: Additional author and exact solutions to the SIC problem in dimension
16 adde
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