Holographic Spacetimes as Quantum Circuits of Path-Integrations

We propose that holographic spacetimes can be regarded as collections of quantum circuits based on path-integrals. We relate a codimension one surface in a gravity dual to a quantum circuit given by a path-integration on that surface with an appropriate UV cut off. Our proposal naturally generalizes the conjectured duality between the AdS/CFT and tensor networks. This largely strengthens the surface/state duality and also provides a holographic explanation of path-integral optimizations. For static gravity duals, our new framework provides a derivation of the holographic complexity formula given by the gravity action on the WDW patch. We also propose a new formula which relates numbers of quantum gates to surface areas, even including time-like surfaces, as a generalization of the holographic entanglement entropy formula. We argue the time component of the metric in AdS emerges from the density of unitary quantum gates in the dual CFT. Our proposal also provides a heuristic understanding how the gravitational force emerges from quantum circuits.Comment: 39 pages, 13 figures, latex; v2: appendix B added for an explicit analysis of path-integral quantum circuits, counting scrambling quantum gates clarified, references included; v3: a reference adde

User association in 5G heterogeneous networks exploiting multi-slope path loss model

Traffic offloading via small cells is important to realize the benefits of multi-tier heterogeneous networks (HetNets). Currently, the user association techniques are under the influence of single slope path loss model. The densification of networks and irregular cell patterns have increased the variations in both the link distances and interferences; making single slope path loss models less accurate. In this paper, we consider the downlink of a HetNet with picocells overlaid on a macrocell and propose a framework for user association with dual slope path loss model. Simulation results show that the dual slope model improves the system performance compared to the standard single slope model by offloading more traffic from macro-tier to pico-tier; the effect being more significant at higher edge user density. Furthermore, the user association is highly dependent on the path loss exponents in a dual slope model

Spare capacity allocation using shared backup path protection for dual link failures

This paper extends the spare capacity allocation (SCA) problem from single link failure [1] to dual link failures on mesh-like IP or WDM networks. The SCA problem pre-plans traffic flows with mutually disjoint one working and two backup paths using the shared backup path protection (SBPP) scheme. The aggregated spare provision matrix (SPM) is used to capture the spare capacity sharing for dual link failures. Comparing to a previous work by He and Somani [2], this method has better scalability and flexibility. The SCA problem is formulated in a non-linear integer programming model and partitioned into two sequential linear sub-models: one finds all primary backup paths first, and the other finds all secondary backup paths next. The results on five networks show that the network redundancy using dedicated 1+1+1 is in the range of 313-400%. It drops to 96-181% in 1:1:1 without loss of dual-link resiliency, but with the trade-off of using the complicated share capacity sharing among backup paths. The hybrid 1+1:1 provides intermediate redundancy ratio at 187-310% with a moderate complexity. We also compare the passive/active approaches which consider spare capacity sharing after/during the backup path routing process. The active sharing approaches always achieve lower redundancy values than the passive ones. These reduction percentages are about 12% for 1+1:1 and 25% for 1:1:1 respectively