# Quantum Class 10, Thu 2022-09-29

## 1 IEEE Quantum Week 2022

This conference was last week. It was expensive but you can get something for free thus. Look at https://qce.quantum.ieee.org/2022/home/program/keynotes/

to see current important topics. Then google the speakers and titles to look for free versions of their presentations.

You could also pay for virtual access for 3 months.

https://people.cs.uchicago.edu/~ftchong/Chong-QC-UCLA19.pdf

## 2 Quantum properties - Phase

1. You cannot measure the phase of qbit.

2. You can measure the relative phase of 2 qbits.

3. Many algorithms encode the answer as a phase shift of a qbit.

4. Phase kickback means that a gate that runs one way, e.g., the control bit affects an output bit, can be made to run the other way, e.g., the control bit is changed, by making the other bit a Hadamad basis.

5. Phase Kickback V Abhijith Rao

6. Qiskit Phase Kickback

## 3 Deutsch Jozsa Algorithm, ctd

The problem is artificial and uninteresting by itself. Its importance is that it was the first problem with a faster quantum algorithm (than its classical algorithm). It's a proof of principle.

This is a nice detailed description:

https://en.wikipedia.org/wiki/Deutsch%E2%80%93Jozsa_algorithm

We're following: https://qiskit.org/textbook/ch-algorithms/deutsch-jozsa.html

Then the next step is to find a more interesting problem that can be sped up.

## 4 Bernstein-Vazirani Algorithm

This would be that next step.

https://qiskit.org/textbook/ch-algorithms/bernstein-vazirani.html

## 5 Simon's periodicity

Blackbox $F: \{0,1\}^n \to \{0,1\}^n$

For some unknown $c$, $F(x\oplus c) = F(x)$.

Determine $c$.