### Quantum Operations

- Classical: Bitflip
- Quantum: Rotations about some axis
- Quantum: Measurement is the overlap between the state and some basis vector

### Quantum Measurement

- Requires a basis
- Outcomes are non-deterministic
- Destroys phase information, only can measure once

### Quantum System Properties

- No-Cloning Theorem: Quantum states cannot be copied
- Entanglement: The state of a qubit is "correlated" with the state of another qubit
- You cannot describe the effect of a rotation on only one qubit in set of entangled qubits

### A Pathological Example

### A Pathological Example

### Quantum Algorithms

Deutch-Jozsa: Free$^{*}$ parallelism, reduces from $O(2^{n-1})$ to $O(1)$ function calls

Grover's Algorithm: Search an unsorted list for an$^{**}$ element in $O(\sqrt{n})$, best classical is $O(n)$

Shor's Algorithm: A faster prime factoring algorithm, because fourier transforms are unitary

### Shor's Algorithm

GNFS: Generate polynomials and hope that their roots form a smooth ring such that the 'square root' of the ring is a homomorphism to the prime factors

Shor's algorithm: Find the period of the prime field using the quantum fourier transform, the 'square root' then gives the prime factors

## Common Myths and Misconceptions

Quantum computers are **NOT** universally faster or more powerful than classical computers

Quantum computers will **NOT** be here tomorrow.

have:100 qubits / need: 100 million

Dwave is ** NOT ** a quantum computer. Evidence shows quantum annealer at best

There is no one right material or system to make qubits

## Why don't we all have quantum keys?

Hardware developments

Distance/Loss: $\approx 300$ km

Realistic device security models

###
One approach to

overcoming loss:

QKD receiver satellite

# QKD Hardware Security:

### Functionality $\neq$ security

### Commercial QKD devices

### QKD receiver satellite

## Single photon detector unit

## Integrated optical assembly (IOA)

## Acquisition pointing and tracking (APT)