Integrated electronic optical switches in future chip ion

trap

Shu, GangShu, Gang

5/24/20065/24/2006

Basic concepts of Quantum ComputerBasic concepts of Quantum Computer

Ion trap technologyIon trap technology

Optical Switches in future trapsOptical Switches in future trapsConclusionsConclusions

Basic concepts of Quantum ComputerBasic concepts of Quantum Computer

Ion trap technologyIon trap technology

Optical Switches in future trapsOptical Switches in future trapsConclusionsConclusions

A quantum computer is any device for A quantum computer is any device for computationcomputation that makes direct use of that makes direct use of

distinctively distinctively quantum mechanicalquantum mechanical phenomena, such as phenomena, such as superpositionsuperposition and and entanglemententanglement, to perform operations , to perform operations

on data.on data.

A computer architecture must include two fundamental A computer architecture must include two fundamental elements:elements:

1.1. A mathematics system that can represent and solve A mathematics system that can represent and solve general problems.general problems.

2.2. A physical system that can realize the mathematics A physical system that can realize the mathematics system.system.

Classical computers are based on real space and realized by macro physics Classical computers are based on real space and realized by macro physics laws (electronics)laws (electronics)

Quantum computers are based on functional spaces and realized by quantum Quantum computers are based on functional spaces and realized by quantum mechanics.mechanics.

Quantum computers supply a new way to express and attack hard problems. Quantum computers supply a new way to express and attack hard problems.

Any other ways? QFT?Any other ways? QFT?

Well, any realizable system described by a special mathematics may be a Well, any realizable system described by a special mathematics may be a choice.choice.

Why QC?Why QC?

1.1. We’re approaching the limit of classical chip. The linear We’re approaching the limit of classical chip. The linear increasing computation ability will never catch up with increasing computation ability will never catch up with nonlinear increasing complexity.nonlinear increasing complexity.

So, what?So, what? Quantum Algorithms and QCQuantum Algorithms and QC

2.2. Physicists never forget physics: Physicists never forget physics: We want to study complicated quantum system, why not We want to study complicated quantum system, why not

simulate it with a quantum device?simulate it with a quantum device?

3.3. If QC is only a dream, maybe Quantum Algorithms will If QC is only a dream, maybe Quantum Algorithms will shine light to some hard problems. shine light to some hard problems.

Does it work?Does it work?

No universal algorithm yet No universal algorithm yet

BUT BUT some very promising ones such as Shor’s fasome very promising ones such as Shor’s fa

ctoring algorithmctoring algorithm

which will cause trouble to traditional information security awhich will cause trouble to traditional information security a

nd push people to Quantum information…nd push people to Quantum information…

QC’s secretQC’s secret

Q Q bitbit

A state vector carrying all information and A state vector carrying all information and our hope.our hope.

Basic concepts of Quantum ComputerBasic concepts of Quantum Computer

Ion trap technologyIon trap technology

Optical Switches in future trapsOptical Switches in future trapsConclusionsConclusions

Why Ion traps?Why Ion traps?

Need a quantum system well isolated from Need a quantum system well isolated from environmentenvironment

Need some interactions turned on and off as Need some interactions turned on and off as wish wish

Trapped single ions are isolated from each otherTrapped single ions are isolated from each other

Lasers are nice and controllable, to cool and operate the Lasers are nice and controllable, to cool and operate the ionsions

What is a Paul trap?What is a Paul trap?

Use rotating hyperbolic electric field to form a pseudo potential well to trap a ion, and use laser to cool the ion

If a computer, not a single QbitIf a computer, not a single QbitA possible QC schemeA possible QC scheme

Our trap and ions

Basic concepts of Quantum ComputerBasic concepts of Quantum Computer

Ion trap technologyIon trap technology

Optical Switches for future trapsOptical Switches for future traps

ConclusionsConclusions

Easiest to think of but not easy to doEasiest to think of but not easy to do Mirror ArrayMirror Array

Drawbacks:Drawbacks:

SlowSlowVibrationVibration

Not so reliableNot so reliable

So what?So what?

Optical Switches using EO effectOptical Switches using EO effect

Very fast !Very fast !

Very reliable ! – Very reliable ! – no moving partsno moving parts

Easier to build ! – Easier to build ! – just layersjust layers

AndAndexpen$ive expen$ive

Some basic computationsSome basic computationsUse 493nm blue light as example:Use 493nm blue light as example:

Waveguide dimension guided wave profile two guides coupling

100% coupling: L=1.09966mm

dn=0.000540554

Some designsSome designs

Use integrated wave guide instead of free space to propagate lasers.Use integrated wave guide instead of free space to propagate lasers.

Use simplified electro optical switches to control lasers.Use simplified electro optical switches to control lasers.

The trap and the wave guide.The trap and the wave guide.

Basic concepts of Quantum ComputerBasic concepts of Quantum Computer

Ion trap technologyIon trap technology

Optical Switches for future trapsOptical Switches for future traps

ConclusionsConclusions

1.1. Ion trap is one of the most promising methods to Ion trap is one of the most promising methods to implement quantum computer.implement quantum computer.

2.2. Integrated device is the only way to scale up.Integrated device is the only way to scale up.

What else can be integrated?What else can be integrated?

Laser diodesLaser diodes

ModulatorsModulators

Thank you!

Shu, Gang

Dept. of Phys.

5.24.06