# Category Archives: QUANTUM PHYSICS

# Quantum Computing and the Entanglement Frontier

**John Preskill, CalTech**

The quantum laws governing atoms and other tiny objects seem to defy common sense, and information encoded in quantum systems has weird properties that baffle our feeble human minds. John Preskill will explain why he loves quantum entanglement, the elusive feature making quantum information fundamentally different from information in the macroscopic world. By exploiting quantum entanglement, quantum computers should be able to solve otherwise intractable problems, with far-reaching applications to cryptology, materials, and fundamental physical science. Preskill is less weird than a quantum computer, and easier to understand.

# The Black Hole information problem: past, present, and future

**Donald Marolf**

We give a brief overview of the black hole information problem emphasizing fundamental issues and recent proposals for its resolution. The focus is on broad perspective and providing a guide to current literature rather than presenting full details. We concentrate on resolutions restoring naive unitarity…

Read more at https://arxiv.org/pdf/1703.02143.pdf

# Quantum Information and Spacetime

John Preskill, Caltech

QIP 2017, 15 Jan 2017

http://www.theory.caltech.edu/~preskill/talks/QIP2017-tutorial-Preskill.pdf

# Quantum communication with photons

**Mario Krenn, Mehul Malik, Thomas Scheidl, Rupert Ursin, Anton Zeilinger**

The secure communication of information plays an ever increasing role in our society today. Classical methods of encryption inherently rely on the difficulty of solving a problem such as finding prime factors of large numbers and can, in principle, be cracked by a fast enough machine. The burgeoning field of quantum communication relies on the fundamental laws of physics to offer unconditional information security. Here we introduce the key concepts of quantum superposition and entanglement as well as the no-cloning theorem that form the basis of this field. Then, we review basic quantum communication schemes with single and entangled photons and discuss recent experimental progress in ground and space-based quantum communication. Finally, we discuss the emerging field of high-dimensional quantum communication, which promises increased data rates and higher levels of security than ever before. We discuss recent experiments that use the orbital angular momentum of photons for sharing large amounts of information in a secure fashion.

Read more at https://arxiv.org/pdf/1701.00989v1.pdf

# Quantum papers of 2016

1. The Mathematics of Entanglement

Fernando G.S.L. Brandao, Matthias Christandl, Aram W. Harrow, Michael Walter: https://arxiv.org/pdf/1604.01790.pdf

2. Quantum Shannon Theory

John Preskill: https://arxiv.org/pdf/1604.07450.pdf