111 research outputs found
Localization and Higher Spin/CFT Dualities
Localization is a powerful tool to compute physical quantities such as partition functions, free energies and expectation values of certain operators exactly at any coupling in many supersymmetric theories. Due to this merit, the technique is able to provide highly nontrivial tests of AdS/CFT correspondence. We apply localization procedure to the most general three-dimensional N = 1 Chern-Simons matter theories, which are not studied in the previous localization literature, and show that they can also be formally localized. The other focus in this body of work is the study of an important aspect of high energy physics, the higher spin theories, and their conjectured CFT duals. Higher spin theory is a remarkable extension of Einstein gravity in which mass particles of all spin are described by self-consistent and fully nonlinear field equations. We perform tests of the duality between supersymmetric higher spin theories in AdS4 and the corresponding CFTs, by comparisons of the one loop free energies on both sides. We show that the mismatch between the free energies in the duality between Type-B higher spin theory/fermionic vector model cannot be solved by the introduction of supersymmetry. We then turn to another test of the HS/CFT correspondence, by comparing the tree-level three-point functions on both sides. We produce the full structures of three-point Witten diagrams for both parity-preserving and parity-violating bosonic HS theories, and show that they match perfectly with the corresponding ones on CFT side
ABJ Quadrality
We study physical consequences of adding orientifolds to the ABJ triality,
which is among 3d N=6 superconformal Chern-Simons theory known as ABJ theory,
type IIA string in AdS_4 x CP^3 and N=6 supersymmetric (SUSY) Vasiliev higher
spin theory in AdS_4. After adding the orientifolds, it is known that the gauge
group of the ABJ theory becomes O(N_1)xUSp(2N_2) while the background of the
string theory is replaced by AdS_4 x CP^3/Z_2, and the supersymmetries in the
both theories reduce to N=5. We propose that adding the orientifolds to the N=6
Vasiliev theory leads to N=5 SUSY Vasiliev theory. It turns out that the N=5
case is more involved because there are two formulations of the N=5 Vasiliev
theory with either O or USp internal symmetry. We show that the two N=5
Vasiliev theories can be understood as certain projections of the N=6 Vasiliev
theory, which we identify with the orientifold projections in the Vasiliev
theory. We conjecture that the O(N_1)xUSp(2N_2) ABJ theory has the two vector
model like limits: N_2 >> N_1 and N_1 >> N_2 which correspond to the
semi-classical N=5 Vasiliev theories with O(N_1) and USp(2N_2) internal
symmetries respectively. These correspondences together with the standard
AdS/CFT correspondence comprise the ABJ quadrality among the N=5 ABJ theory,
string/M-theory and two N=5 Vasliev theories. We provide a precise holographic
dictionary for the correspondences by comparing correlation functions of stress
tensor and flavor currents. Our conjecture is supported by various evidence
such as agreements of the spectra, one-loop free energies and SUSY enhancement
on the both sides. We also predict the leading free energy of the N=5 Vasiliev
theory from the CFT side. As a byproduct, we give a derivation of the relation
between the parity violating phase in the N=6 Vasiliev theory and the
parameters in the N=6 ABJ theory, which was conjectured in arXiv:1207.4485.Comment: 38+15 pages, 4 figures; v2: minor correction
Chern-Simons Matter Theories and Higher Spin Gravity
We compute the parity violating three point amplitudes with one scalar leg in
higher spin gravity and compare results with those of Chern-Simons matter
theories. The three-point correlators of the free boson, free fermion, critical
vector model and Gross-Neveu model are reproduced including the dependence on
the Chern-Simons coupling. We also perform a simple test of the modified higher
spin equations proposed in arXiv:1605.02662 [hep-th] and find that the results
are consistent with the AdS/CFT correspondence.Comment: 39 pages; minor corrections and refs adde
Thermostat-assisted continuously-tempered Hamiltonian Monte Carlo for Bayesian learning
We propose a new sampling method, the thermostat-assisted
continuously-tempered Hamiltonian Monte Carlo, for Bayesian learning on large
datasets and multimodal distributions. It simulates the Nos\'e-Hoover dynamics
of a continuously-tempered Hamiltonian system built on the distribution of
interest. A significant advantage of this method is that it is not only able to
efficiently draw representative i.i.d. samples when the distribution contains
multiple isolated modes, but capable of adaptively neutralising the noise
arising from mini-batches and maintaining accurate sampling. While the
properties of this method have been studied using synthetic distributions,
experiments on three real datasets also demonstrated the gain of performance
over several strong baselines with various types of neural networks plunged in
Interference-aware coordinated power allocation in autonomous Wi-Fi environment
Self-managed access points (APs) with growing intelligence can optimize their own performances but pose potential negative impacts on others without energy ef ciency. In this paper, we focus on modeling the coordinated interaction among interest-independent and self-con gured APs, and conduct the power allocation case study in the autonomous Wi-Fi scenario. Speci cally, we build a `coordination Wi-Fi platform (CWP), a public platform for APs interacting with each other. OpenWrt-based APs in the physical world are mapped to virtual agents (VAs) in CWP, which communicate with each other through a standard request-reply process de ned as AP talk protocol (ATP).With ATP, an active interference measurement methodology is proposed re ecting both in-range interference and hidden terminal interference, and the Nash bargaining-based power control is further formulated for interference reductions. CWP is deployed in a real of ce environment, where coordination interactions between VAs can bring a maximum 40-Mb/s throughput improvement with the Nash bargaining-based power control in the multi-AP experiments
Grasp Multiple Objects with One Hand
The human hand's complex kinematics allow for simultaneous grasping and
manipulation of multiple objects, essential for tasks like object transfer and
in-hand manipulation. Despite its importance, robotic multi-object grasping
remains underexplored and presents challenges in kinematics, dynamics, and
object configurations. This paper introduces MultiGrasp, a two-stage method for
multi-object grasping on a tabletop with a multi-finger dexterous hand. It
involves (i) generating pre-grasp proposals and (ii) executing the grasp and
lifting the objects. Experimental results primarily focus on dual-object
grasping and report a 44.13% success rate, showcasing adaptability to unseen
object configurations and imprecise grasps. The framework also demonstrates the
capability to grasp more than two objects, albeit at a reduced inference speed
MSRL: Distributed Reinforcement Learning with Dataflow Fragments
Reinforcement learning (RL) trains many agents, which is resource-intensive
and must scale to large GPU clusters. Different RL training algorithms offer
different opportunities for distributing and parallelising the computation.
Yet, current distributed RL systems tie the definition of RL algorithms to
their distributed execution: they hard-code particular distribution strategies
and only accelerate specific parts of the computation (e.g. policy network
updates) on GPU workers. Fundamentally, current systems lack abstractions that
decouple RL algorithms from their execution.
We describe MindSpore Reinforcement Learning (MSRL), a distributed RL
training system that supports distribution policies that govern how RL training
computation is parallelised and distributed on cluster resources, without
requiring changes to the algorithm implementation. MSRL introduces the new
abstraction of a fragmented dataflow graph, which maps Python functions from an
RL algorithm's training loop to parallel computational fragments. Fragments are
executed on different devices by translating them to low-level dataflow
representations, e.g. computational graphs as supported by deep learning
engines, CUDA implementations or multi-threaded CPU processes. We show that
MSRL subsumes the distribution strategies of existing systems, while scaling RL
training to 64 GPUs
LIGS: Learnable Intrinsic-Reward Generation Selection for Multi-Agent Learning
Efficient exploration is important for reinforcement learners to achieve high
rewards. In multi-agent systems, coordinated exploration and behaviour is
critical for agents to jointly achieve optimal outcomes. In this paper, we
introduce a new general framework for improving coordination and performance of
multi-agent reinforcement learners (MARL). Our framework, named Learnable
Intrinsic-Reward Generation Selection algorithm (LIGS) introduces an adaptive
learner, Generator that observes the agents and learns to construct intrinsic
rewards online that coordinate the agents' joint exploration and joint
behaviour. Using a novel combination of MARL and switching controls, LIGS
determines the best states to learn to add intrinsic rewards which leads to a
highly efficient learning process. LIGS can subdivide complex tasks making them
easier to solve and enables systems of MARL agents to quickly solve
environments with sparse rewards. LIGS can seamlessly adopt existing MARL
algorithms and, our theory shows that it ensures convergence to policies that
deliver higher system performance. We demonstrate its superior performance in
challenging tasks in Foraging and StarCraft II.Comment: arXiv admin note: text overlap with arXiv:2103.0915
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