Build Your Own Quantum Computer for Fun and Profit! Stephen Granade.

Build Your Own Quantum Computer for Fun and Profit!

Stephen Granade

Bits are 1s and 0s (i.e. base 2)

16 8 4 2 1

16 2 1 + + = 191 00 11

Save Us, Gordon Moore!

Parallel ComputationTakes More Space

Photo credit: pure_martin

Light Polarization States

Vertical light:

Horizontal light:

A mix:

2

1

2

1

Amplitudes

Square for probabilities: 2

1,

2

1

What’s Going On With The 3 Polarizers

Vertical polarizer:

Horizontal polarizer: nada

What’s Going On With The 3 Polarizers

Vertical polarizer:

45 degree polarizer:

Horizontal polarizer:

2

1

2

1

Bits Hold 1 NumberQubits Can Hold All Numbers!

111110

101100

011010

001000

81

101

3-Bit Number 3-Qubit Number

Superposition makesthis possible

Tangent: Entanglement Happens When One Qubit’s State Depends on

Another’s

11002

1 01002

1

Entangled Not Entangled

If you measure the firstqubit and it’s 0, you knowthe second qubit is 0 too.

They’re entangled!

If you measure the firstqubit and it’s 0, you don’tknow the second qubit.They’re independent!

You Can Add All Numbers At Once!

1001101

11010121003

11410301200

441

111001004

1

111001004

1

Classical Computer Quantum Computer

Public

It’s Just an Algorithm

Private

n

n

qped

qpn

qp

d

e

modencryptmsg

modmsgencrypt

11mod1

prime) largevery (,Choose

Turning Factoring into Period Finding

,mod,mod

,mod,mod43

2

nxnx

nxnx

If n has the factors p and q,then, if you pick a random x,the above sequence has aperiod that evenly dividesinto (p-1)(q-1)

Leonhard Euler

Shor’s Algorithm is Fast

3/1log2O n

3logO n

Classical factoring

Shor’s Algorithm

Grover’s Algorithm Finds Stuff QuicklySearches unsorted data

Photo credit: seanabrady

Number of items Approx. Speedup

100 10

1,000 32

10,000 100

100,000 316

1,000,000 1000

10,000,000 3162

100,000,000 10000

1,000,000,000 31623

Decoherence Smears Out States

dead2

1alive

2

1

dead

There are Lots of Ways to Make a Quantum Computer

PhotonsTrapped Ions

Optical Lattice

Liquid NMRSpintronics

7-Qubit Computer from IBM

15

3 5

Factored

2001. Chuang et. al.

First Qubyte from Innsbruck

Quantum Computer Onna Chip

Sadly I have no good pictures of the group or its research besides this graphic from the cover of Science

D-Wave…maybe