76,441 research outputs found

    Driving three atoms into a singlet state in an optical cavity via adiabatic passage of a dark state

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    In this paper, we propose an efficient scheme to drive three atoms in an optical cavity into a singlet state via adiabatic passage. Appropriate Rabi frequencies of the classical fields are selected to realize the present scheme. The scheme is robust against deviations in the pulse delay and laser intensity through some simple analysis of the adiabatic condition. It is notable that the estimated range of the effective adiabaticity condition coincides with the numerical results. When taking dissipation into account, we show that the process is immune to atomic spontaneous emission as the atomic excited states are never populated in adiabatic evolution. Moreover, under certain conditions, the cavity decay can also be efficiently suppressed

    Property Tax and Urban Sprawl: Theory and Implications for U.S. Cities

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    This article attempts a formal analysis of the connection between property tax and urban sprawl in U.S. cities. We develop a theoretical model that includes households (who are also landlords) and land developers in a regional land market. We then test the model empirically based on a national sample of urbanized areas. The results we obtained from both theoretical and empirical analyses indicate that increasing property tax rates reduces the size of urbanized areas.Urban Sprawl; Full Closed City; Urban Economics; Property Tax; Instrumental Variables

    Vertex operator algebras of Argyres-Douglas theories from M5-branes

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    We study aspects of the vertex operator algebra (VOA) corresponding to Argyres-Douglas (AD) theories engineered using the 6d N=(2, 0) theory of type JJ on a punctured sphere. We denote the AD theories as (Jb[k],Y)(J^b[k],Y), where Jb[k]J^b[k] and YY represent an irregular and a regular singularity respectively. We restrict to the `minimal' case where Jb[k]J^b[k] has no associated mass parameters, and the theory does not admit any exactly marginal deformations. The VOA corresponding to the AD theory is conjectured to be the W-algebra Wk2d(J,Y)\mathcal{W}^{k_{2d}}(J,Y), where k2d=βˆ’h+bb+kk_{2d}=-h+ \frac{b}{b+k} with hh being the dual Coxeter number of JJ. We verify this conjecture by showing that the Schur index of the AD theory is identical to the vacuum character of the corresponding VOA, and the Hall-Littlewood index computes the Hilbert series of the Higgs branch. We also find that the Schur and Hall-Littlewood index for the AD theory can be written in a simple closed form for b=hb=h. We also test the conjecture that the associated variety of such VOA is identical to the Higgs branch. The M5-brane construction of these theories and the corresponding TQFT structure of the index play a crucial role in our computations.Comment: 35 pages, 1 figure, v2: minor corrections, referenced adde

    (0,4)(0, 4) dualities

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    We study a class of two-dimensional N=(0,4){\cal N}=(0, 4) quiver gauge theories that flow to superconformal field theories. We find dualities for the superconformal field theories similar to the 4d N=2{\cal N}=2 theories of class S{\cal S}, labelled by a Riemann surface C{\cal C}. The dual descriptions arise from various pair-of-pants decompositions, that involves an analog of the TNT_N theory. Especially, we find the superconformal index of such theories can be written in terms of a topological field theory on C{\cal C}. We interpret this class of SCFTs as the ones coming from compactifying 6d N=(2,0){\cal N}=(2, 0) theory on CP1Γ—C\mathbb{CP}^1 \times {\cal C}Comment: 41 pages, 12 figure
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