Testing the first law of black hole mechanics with gravitational waves

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe,particularly black holes.In this study,we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics,employing two different approaches.We consider the secondary compact object as a perturbation to the primary black hole before the merger,and the remnant black hole as a stationary black hole after the merger.In the pre-merger and post-merger analysis,our results demonstrate consistency with the first law,with an error level of approximate 25%at a68%credibility level for GW190403051519.In the full inspiral-merger-ringdown analysis,our results show consistency with the first law of black hole mechanics,with an error level of about 6%at a 68%credibility level and 10%at a 95%credibility level for GW191219163120.Additionally,we observe that the higher the mass ratio of the gravitational wave source,the more consistent our results are with the first law of black hole mechanics.Overall,our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

Quantum bit threads of MERA tensor network in large c limit

The Ryu-Takayanagi(RT)formula plays a large role in the current theory of gauge-gravity duality and emergent geometry phenomena.The recent reinterpretation of this formula in terms of a set of"bit threads"is an interesting effort in understanding holography.In this study,we investigate a quantum generalization of the"bit threads"based on a tensor network,with particular focus on the multi-scale entanglement renormalization ansatz(MERA).We demonstrate that,in the large c limit,isometries of the MERA can be regarded as"sources"(or"sinks")of the information flow,which extensively modifies the original picture of bit threads by introducing a new variableρ:density of the isometries.In this modified picture of information flow,the isometries can be viewed as generators of the flow.The strong subadditivity and related properties of the entanglement entropy are also obtained in this new picture.The large c limit implies that classical gravity can emerge from the information flow.