We present exact results for partition functions of Jackiw-Teitelboim (JT) gravity on two-dimensional surfaces of arbitrary genus with an arbitrary number of boundaries. The boundaries are of the type relevant in the NAdS${}_2$/NCFT${}_1$ correspondence. We show that the partition functions correspond to the genus expansion of a certain matrix integral. A key fact is that Mirzakhani's recursion relation for Weil-Petersson volumes maps directly onto the Eynard-Orantin "topological recursion" formulation of the loop equations for this matrix integral. The matrix integral provides a (non-unique) nonperturbative completion of the genus expansion, sensitive to the underlying discreteness of the matrix eigenvalues. In matrix integral descriptions of noncritical strings, such effects are due to an infinite number of disconnected worldsheets connected to D-branes. In JT gravity, these effects can be reproduced by a sum over an infinite number of disconnected geometries -- a type of D-brane logic applied to spacetime.

JT gravity as a matrix integral

A primer on resurgent transseries and their asymptotics

As CMOS technology begins to face significant scaling challenges, considerable research efforts are being directed to investigate alternative device technologies that can serve as a replacement for CMOS. Spintronic devices, which utilize the spin of electrons as the state variable for computation, have recently emerged as one of the leading candidates for post-CMOS technology. Recent experiments have shown that a nano-magnet can be switched by a spin-polarized current and this has led to a number of novel device proposals over the past few years. In this paper, we provide a review of different mechanisms that manipulate the state of a nano-magnet using current-induced spin-transfer torque and demonstrate how such mechanisms have been engineered to develop device structures for energy-efficient on-chip memory and logic.

Spin-Transfer Torque Devices for Logic and Memory: Prospects and Perspectives

We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of standard model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the [Formula: see text]m scale up to the Big Bang Nucleosynthesis limit of [Formula: see text] m. Neutral LLPs with lifetimes above [Formula: see text]100 m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging backgrounds, triggers, and small acceptances. MATHUSLA is a proposal for a minimally instrumented, large-volume surface detector near ATLAS or CMS. It would search for neutral LLPs produced in HL-LHC collisions by reconstructing displaced vertices (DVs) in a low-background environment, extending the sensitivity of the main detectors by orders of magnitude in the long-lifetime regime. We study the LLP physics opportunities afforded by a MATHUSLA-like detector at the HL-LHC, assuming backgrounds can be rejected as expected. We develop a model-independent approach to describe the sensitivity of MATHUSLA to BSM LLP signals, and compare it to DV and missing energy searches at ATLAS or CMS. We then explore the BSM motivations for LLPs in considerable detail, presenting a large number of new sensitivity studies. While our discussion is especially oriented towards the long-lifetime regime at MATHUSLA, this survey underlines the importance of a varied LLP search program at the LHC in general. By synthesizing these results into a general discussion of the top-down and bottom-up motivations for LLP searches, it is our aim to demonstrate the exceptional strength and breadth of the physics case for the construction of the MATHUSLA detector.

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Long-lived particles at the energy frontier: the MATHUSLA physics case.

We revisit the symmetries of massless two-dimensional adjoint QCD with gauge group SU(N). The dynamics is not sufficiently constrained by the ordinary symmetries and anomalies. Here we show that the theory in fact admits ∼ 22N non-invertible symmetries which severely constrain the possible infrared phases and massive excitations. We prove that for all N these new symmetries enforce deconfinement of the fundamental quark. When the adjoint quark has a small mass, m ≪ gYM, the theory confines and the non-invertible symmetries are softly broken. We use them to compute analytically the k-string tension for N ≤ 5. Our results suggest that the k-string tension, Tk, is Tk ∼ |m| sin(πk/N) for all N. We also consider the dynamics of adjoint QCD deformed by symmetric quartic fermion interactions. These operators are not generated by the RG flow due to the non-invertible symmetries, thus violating the ordinary notion of naturalness. We conjecture partial confinement for the deformed theory by these four-fermion interactions, and prove it for SU(N ≤ 5) gauge theory. Comparing the topological phases at zero and large mass, we find that a massless particle ought to appear on the string for some intermediate nonzero mass, consistent with an emergent supersymmetry at nonzero mass. We also study the possible infrared phases of adjoint QCD allowed by the non-invertible symmetries, which we are able to do exhaustively for small values of N. The paper contains detailed reviews of ideas from fusion category theory that are essential for the results we prove.

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Symmetries and strings of adjoint QCD2

QCD-like theories can be engineered to remain in a confined phase when compactified on an arbitrarily small circle, where their features may be studied quantitatively in a controlled fashion. Previous work has elucidated the generation of a nonperturbative mass gap and the spontaneous breaking of chiral symmetry in this regime. Here, we study the rich spectrum of hadronic states, including glueball, meson, and baryon resonances. We find an exponentially growing Hagedorn density of states, as well as the emergence of nonperturbative energy scales given by iterated exponentials of the inverse Yang-Mills coupling ${g}^{2}$.

QCD on a small circle

Emerging nonvolatile resistive memory technologies can be potentially suitable for computationally expensive analog pattern-matching tasks. However, the use of CMOS analog circuits with resistive crossbar memory (RCM) would result in large power consumption and poor scalability, thereby eschewing the benefits of RCM-based computation. We explore the potential of emerging spin-torque devices for RCM-based approximate computing circuits. Emerging spin-torque switching techniques may lead to nanoscale, current-mode spintronic switches that can be used for energy-efficient analog-mode data processing. We propose the use of such low-voltage, fast-switching, magnetometallic “spin neurons” for ultralow power non-Boolean computing with RCM. We present the design of analog associative memory for face recognition using RCM, where, substituting conventional analog circuits with spin neurons can achieve ~100× lower power consumption.

Energy-Efficient Non-Boolean Computing With Spin Neurons and Resistive Memory

The authors propose an innovative scenario that can explain the matter-antimatter asymmetry. The proposal is based on a low-scale baryogenesis model, in which Majorana fermions mediate heavy baryon-antibaryon oscillations. The authors investigate ways in which some of these new Majorana fermions may be produced at colliders.

Baryogenesis from oscillations of charmed or beautiful baryons

We establish the action of three-dimensional bosonization and particle-vortex duality in the presence of a boundary, which supports a non-anomalous two-dimensional theory. We confirm our prescription using a microscopic realization of the duality in terms of a Euclidean lattice.

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3d Abelian Dualities with Boundaries

We use 3d bosonization dualities to derive new non-supersymmetric dualities between bosonic quiver theories in 2 + 1 dimensions. It is shown that such dualities are a natural non-Abelian generalization of the bosonic particle-vortex duality. A special case of such dualities is applicable to Chern-Simons theories living on interfaces in 3 + 1 dimensional SU(N) Yang-Mills theory across which the theta angle jumps. We also analyze such interfaces in a holographic construction which provides further evidence for novel dualities between quiver gauge theories and gauge theories with adjoint scalars. These conjectured dualities pass some stringent consistency tests.

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Kyle Aitken

Papers

QCD on a small circle

Energy-Efficient Non-Boolean Computing With Spin Neurons and Resistive Memory

Baryogenesis from oscillations of charmed or beautiful baryons

3d Abelian Dualities with Boundaries

Novel 3d bosonic dualities from bosonization and holography