This weekend, I finally got around to listen to these talks that I had marked down. All of those that I have mentioned below are worth listening, even if there are old videos. All the videos are hosted at Perimeter Institute.

**Large Extra Dimensions – ISSYP Keynote Session**

Speaker: Sabine Hossenfelder

Abstract: It is an open question why gravity is so much weaker than the other three interactions we know. One possible answer which has been suggested is that this mismatch is only apparently so, and a feature we observe on large distances. The strength of gravity on small distances could grow faster than an extrapolation of Newton’s law would imply, such that it becomes comparable to the other interactions at distances that will be testable in the soon future. The concrete scenario for this is that our world could have additional compactified extra dimensions. If that was the case, quantum gravitational effects could become observable at the Large Hadron Collider. The most prominent features in these models are the production of mini black holes, and graviton emission.

**The Black Hole Wars**

Speaker: Leonard Susskind

Abstract: The strange paradoxes and puzzles of the quantum behaviour of black holes and the things that fall into them led to a spirited battle of ideas between Stephen Hawking, Leonard Susskind and other scientists. Resolving the debate may change our entire understanding of space, time, matter and information is the entire world, for example, a quantum hologram?

**NOTE** : This talk is most amusing talk where he narrates the story of Black hole wars which contains characters from Stephan Hawking to George Bush.

Speaker: Michael Nielsen

Abstract: How should we think about quantum computing? The usual answer to this question is based on ideas inspired by computer science, such as qubits, quantum gates, and quantum circuits. In this talk I will explain an alternate geometric approach to quantum computation. In the geometric approach, an optimal quantum computation corresponds to “free falling” along the minimal geodesics of a certain Riemannian manifold. This reformulation opens up the possibility of using tools from geometry to understand the strengths and weaknesses of quantum computation, and perhaps to understand what makes certain physical operations difficult (or easy) to synthesize.

Speaker: Michael Nielsen

Abstract: How can we best take advantage of the internet to improve how science is done? Much attention has been paid to open access and open data as enablers of online innovation. In this talk, I discuss the complementary issue of cultural openness in science, and argue that a relatively closed culture is inhibiting online innovation in science. I’ll discuss ways this culture may be changed, and what opportunities may result.

Speaker: Anne Broadbent

Abstract: I will present a new protocol that was developed entirely in the measurement-based model for quantum computation. Our protocol allows Alice to have Bob carry out a quantum computation for her such that Alice’s inputs, outputs and computation remain perfectly private, and where Alice does not require any quantum computational power or memory. Alice only needs to be able to prepare single qubits from a finite set and send them to Bob, who has the balance of the required quantum computational resources. Our protocol is interactive: after the initial preparation of quantum states, Alice and Bob use two-way classical communication which enables Alice to drive the computation, giving single-qubit measurement instructions to Bob, depending on previous measurement outcomes. Our protocol is efficient and is presented for the special case of a classical-input, and classical-output; modifications allow the general case of quantum inputs and outputs. We also discuss the use of authentication in order for Alice to detect an uncooperative Bob. Based on joint work with Joseph Fitzsimons and Elham Kashefi

Speaker: Stacey Jeffery

Abstract: By exploiting the properties of quantum mechanical systems, two parties can achieve cryptographically secure communication in a manner not possible in a purely classical world, through the process of quantum key distribution. In this talk, I will briefly introduce the field of cryptography and explain one of the most fundamental applications of quantum mechanics to cryptography.

**Demystifying the Higgs Boson [Youtube]**

Speaker : Leonard Susskind