In this talk, Phillip Ball explains why quantum mechanics is not weird.

Quantum computers rely on concepts such as superposition and entanglement that defy our intuitions about how things can behave. It’s often said that the world is quantum-mechanical and weird at small scales, and classical and familiar at human scales.

I will challenge that idea, arguing that the classical world isn’t distinct from the quantum but emerges from it. While we don’t yet have a full understanding of how that happens, the outlines are becoming clear – and in one view, the concept of quantum information lies at the heart of that account. In this talk – which is not-technical and requires no specialist scientific knowledge – I will show address some popular misconceptions about what quantum mechanics means, and explain what we can currently say about what it does mean.

Jason Cong talks about
Compilation for Quantum Computing: Gap Analysis and Optimal Solution

Papers in this session.

From the abstract:

As quantum computing devices continues to scale up, we would like to access the quality of the existing quantum compilation (or design automation) tools. As the first step, we focus on the layout synthesis step. We develop a novel method to construct a family of quantum circuits with known optimal, QUEKO, which have known optimal depths and gate counts on a given quantum device coupling graph. With QUEKO, we evaluated several leading industry and academic LSQC tools, including Cirq from Google, Qiskit from IBM, and t|ket from CQC.

We found rather surprisingly large optimality gaps, up to 45x on even near-term feasible circuits. Then, we went on to develop a tool for optimal layout synthesis for quantum computing, named OLSQ, which formulates LSQC as a mathematical optimization problem. OLSQ more compactly represents the solution space than previous optimal solutions and achieved exponential reduction in computational complexity. 

ExplainingComputers just posted his annual Quantum Computing update.

Quantum computing review, including Google’s quantum supremacy claims, quantum cloud developments (QCaaS), trapped ion quantum computing, and a brief look at Python quantum coding!

More information on quantum computing can be found on his web page at


  • 00:00 Introduction
  • 00:41 Quantum basics
  • 01:56 Quantum supremacy
  • 05:19 Quantum cloud computing
  • 08:10 Trapped ions
  • 09:53 Quantum coding
  • 11:09 Getting there!