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Aaron Slipper

Publications and source records attributed to Aaron Slipper.

7 recordsLinked to original sources

Bosonic codes from compact phase spaces

We present the algebraic structure of bosonic quantum error-correcting codes on genus-two Riemann surfaces. We explicitly construct the code words as automorphic forms and analytically generate the full tower of code spaces at all weights. We prove a fundamental no-go theorem: for any genus greater than one, the stabilizer group is non-amenable, forcing a strictly positive spectral gap in the stabilizer Hamiltonian. Consequently, no normalizable quantum state can satisfy all stabilizer conditions. This sharply contrasts with standard Gottesman-Kitaev-Preskill (GKP) codes, where the amenability of the stabilizer group $\mathbb{Z}^2$ permits approximate code words with arbitrary precision.

quant-ph

Quasi-Classical Braverman--Kazhdan Intertwiners via Quiver Varieties

We show that Braverman--Kazhdan normalized intertwiners for $SL_n(\mathbf{C})$ have a quasi-classical incarnation governed by type $A$ quiver varieties. More precisely, for standard parabolic subgroups $P$ and $P'$ with conjugate Levi subgroups, we construct $SL_n\times L^{\mathrm{ab}}$-equivariant isomorphisms $\Phi(P,P'):\overline{T^*(SL_n/[P,P])}^{\mathrm{aff}}\rightarrow\overline{T^*(SL_n/[P',P'])}^{\mathrm{aff}}$ between the affinizations of the cotangent bundles of the corresponding Braverman--Kazhdan spaces, and we prove that these isomorphisms satisfy Coxeter relations. The construction uses $SL$-gauge analogues of Lusztig--Maffei--Nakajima reflection functors, thereby extending Wang's quiver-variety realization of the quasi-classical Gelfand--Graev action from the Borel case to arbitrary parabolic subgroups. In this way, we complete the quasi-classical Braverman--Kazhdan intertwiner story for $SL_n(\mathbf{C})$ and obtain a systematic source of non-isomorphic varieties whose affinized cotangent bundles are isomorphic.

math.RT

Geometrization of the Schr\"odinger Model for the Minimal Representation of an Even Orthogonal Group: The de Rham Setting

We construct and compare three $D$-module models for the minimal representation of the conformal group of an even-dimensional quadratic space. Let $V$ be a quadratic space over a field $\kappa$ of characteristic $0$, $C\subset V^*$ be the isotropic cone, $\Delta\in D_V$ be the associated Laplace--Beltrami operator, $G$ be the conformal group of $V$, and $D_C$ be the algebra of Grothendieck differential operators on $C$. We prove that the category of finitely generated $D_C$-modules is equivalent both to a Kazhdan--Laumon glued category attached to the smooth locus $C^o$ and to a category of ``harmonic'' twisted $D$-modules on the projective conformal compactification $G/P \supset V$. The gluing is governed by the quadric Fourier transform, while the harmonic model is built from a distinguished $G$-equivariant sheaf $H$ on $G/P$ extending the local quotient $D_V/D_V\Delta$. We prove a new geometric interpretation of higher symmetries of the Laplacian as global sections of $H$, and use this connection to give a geometric proof of the theorem of Levasseur, Smith, and Stafford that $D_C$ is Noetherian despite the singularity of $C$. We also study, via a descent procedure we call ``$F$-moment descent,'' the algebraic geometry of the closure of the minimal nilpotent orbit of $G$, which is the quasiclassical analogue of the minimal representation. Finally, we analyze the filtered structure of $D_V/D_V\Delta$ as a right $D_C$-module, identifying its associated graded layers through a flat degeneration of an affine flag multicone whose special fiber is the Rees space of a natural ideal in $\kappa[\overline{O}_{min}]$.

math.RT

The $\rho$-Fourier transform

Let $G$ be a reductive group over a local field $F$ and let $\rho:{}^LG \to \mathrm{GL}_{V_{\rho}}(\mathbb{C})$ be a representation of its $L$-group satisfying suitable assumptions. Braverman, Kazhdan and Ng\^o conjectured that one has a $\rho$-Fourier transform on $L^2(G(F))$ and a $\rho$-Schwartz space $\mathcal{S}_{\rho}(G(F))<L^2(G(F))$ fixed under the Fourier transform that satisfies certain desiderata. We construct the Fourier transform for arbitrary fields. Over non-Archimedean fields we construct the Schwartz space, and in the Archimedean case we construct an approximation to it. This proves a large portion of their conjectures. Our methods are spectral in nature.

math.NT

Modulation groups

Conjectures of Braverman and Kazhdan, Ng\^o and Sakellaridis have motivated the development of Schwartz spaces for certain spherical varieties. We prove that under suitable assumptions these Schwartz spaces are naturally a representation of a group that we christen the modulation group. This provides a broad generalization of the defining representation of the metaplectic group. The example of a vector space and the zero locus of a quadric cone in an even number of variables are discussed in detail. In both of these cases the modulation group is closely related to algebraic groups, and we propose a conjectural method of linking modulation groups to ind-algebraic groups in general. At the end of the paper we discuss adelization and the relationship between representations of modulation groups and the Poisson summation conjecture.

math.NT

Logarithmic Geometry and Geometric Class Field Theory

We demonstrate an application of logarithmic geometry in the context of geometric Langlands, by providing a logarithmic upgrade of Deligne's geometric class field theory for tamely ramified Galois groups. In particular, we define a framed logarithmic Picard space, and show that a logarithmic compactification of the classical tamely ramified Div-to-Pic map has, for sufficiently large degree, log-simply connected fibers given by logarithmically compactified vector spaces. This provides a canonical bijection between local systems on the curve with divisorial log structure and multiplicative local systems on the framed logarithmic Picard, a logarithmic version of the Hecke eigensheaf correspondence of geometric Langlands for GL_1. We use this to re-derive tamely ramified global Artin reciprocity for function fields, and show that logarithmic geometry allows for a geometric interpretation of local-to-global compatibility at all places, in addition to the unramified places.

math.AG

Parabolic Kazhdan-Laumon and the Kloosterman Fourier Transform for Quadric Cones

Let $G$ be a split reductive group over $F_q$, and let $M$ be a standard Levi subgroup of $G$. Let $Par_M(G)$ denote the set of parabolic subgroups of $G$ with Levi factor $M$. For $P$ and $P'$ in $Par_M(G)$, we let $U=R_u(P)$ and $U'=R_u(P')$ denote the unipotent radicals, and we denote by $\overline{G/U}$ and $\overline{G/U'}$ the affinizations of the corresponding homogeneous spaces. Extending the work of Kazhdan-Laumon and Braverman-Kazhdan (arXiv:math/9809112, arXiv:math/0206119) to general parabolic basic affine, or paraspherical, spaces, we propose a construction for certain intertwining operators $F_{P',P}: S(\overline{G/U}(F_q),C) \to S(\overline{G/U'}(F_q),C)$ for suitable function spaces $S$, defined via kernels analogous to those appearing in those works. We then study the extent to which these intertwiners are normalized. We show that, for opposite $(n-1)+1$ parabolics of $SL_n$, our transform reduces to the classical linear Fourier transform, and that, for opposite unipotents in $SL_3$ or opposite Siegel parabolics in $Sp_4$, our transforms are given by a Fourier transform on a quadric cone, with kernel coming from a Kloosterman sum. We prove Fourier inversion for this transform on a natural subclass of functions on the quadric cone, establishing a finite-field analogue of the quadric Fourier transform of Gurevich-Kazhdan, Getz-Hsu-Leslie, and Kobayashi-Mano (arXiv:2304.13993, arXiv:2103.10261, arXiv:0712.1769).

math.RT