# Presentation: 008358

## Travis S. Humble
Oak Ridge National Laboratory
humblets@ornl.gov

**Travis S. Humble**
- Oak Ridge National Laboratory
- humblets@ornl.gov

**Quantum Teleportation ****with Entangled Multimode Photons**

- PI: Warren Grice

- IC: Susan Durham

- _Agenda_

**Quantum Information and Teleportation**

**Entangled Multimode Photons**

**Teleportation with Multimode Photons**

**Communicating and Computing Applications**

**Sensing and Security Applications**

**2007 IC Postdoctoral Research Fellowship Colloquium**

**Notes:**
2007 IC Postdoctoral Research Fellowship Colloquium, 20 April 2007, Chantilly, VA

## “Information is Physical”

**“****Information is Physical”**

**Notes:**
An outline of the talk, which will start with an introduction to quantum information and the teleportation protocol. The importance of entangled, and entangled photons in particular, will discussed, and an explanation  of teleportation, entanglement swapping, and type-I fusion will be given in terms of a suitable multi-mode analysis.  Finally, we will discuss the use of quantum teleportation for sensing and communication.

## “Information is Physical”

**Entanglement**

**Multiple Qubits**

**“****Information is Physical”**

**Notes:**
An outline of the talk, which will start with an introduction to quantum information and the teleportation protocol. The importance of entangled, and entangled photons in particular, will discussed, and an explanation  of teleportation, entanglement swapping, and type-I fusion will be given in terms of a suitable multi-mode analysis.  Finally, we will discuss the use of quantum teleportation for sensing and communication.

## Quantum Teleportation

**Quantum Teleportation**

****

*****U**j***

- 2. Qubit at 3 encrypted **

- 1. Qubit at 1 destroyed, entanglement expended.

- 3. Encryption key is BSM outcome (2 bits).

- Entanglement
- expended

- 4. Qubit does not traverse intervening space.

**Notes:**
First, an analog to clarify the use of quantum teleportation.
A conventional fax machine transmits information, not paper, between two locations.
Similarly, teleportation transmits qubits of information, not matter.
Particle 1 stores the qubit initially. Particles 2 and 3 are entangled and will act like a quantum communication channel through which the qubit is transferred to particle 3.
To do this, particles 1 and 2 are subjected to a Bell-state measurement, which is a means of jointly measuring two particles.
If successful, particle 3 will be left in a state that is unitarily related to the initial qubit.
Here are the caveats. First, qubit stored in particle 3 is encrypted, and it is encrypted perfectly. In order to recover the information, we have to know the outcome of the Bell-state measurement, and that requires some classical information be sent from here to there. So in short, you don’t get something for nothing.
The second caveat, and why the analogy with a conventional fax machine fails, is that particle 1 now no longer stores any information. The qubit is gone, it is at particle 3. Hence the name teleportation.

## From Theory to Practice

**Quantum system**

**0 **= *h *and **1 **= *v*

**From Theory to Practice**

- Photon

- Qubits may be distinguishable: spatial and spectral modes

- Information may be loss: decoherence and decay

**Notes:**
An outline of the talk, which will start with an introduction to quantum information and the teleportation protocol. The importance of entangled, and entangled photons in particular, will discussed, and an explanation  of teleportation, entanglement swapping, and type-I fusion will be given in terms of a suitable multi-mode analysis.  Finally, we will discuss the use of quantum teleportation for sensing and communication.

## Entangled Multimode Photons

**Pulsed Spontaneous Parametric Down-conversion (SPDC)**

**Entangled Multimode Photons**

**Polarization-entangled single-mode photon pair**

## Entangled Multimode Photons

**Pulsed Spontaneous Parametric Down-conversion (SPDC)**

**Entangled Multimode Photons**

**Polarization-entangled multi-mode photon pair**

## Entangled Multimode Photons

**Pulsed Spontaneous Parametric Down-conversion (SPDC)**

**Entangled Multimode Photons**

- pulsed
- laser

- 

**Type-I SPDC **

**Type-II SPDC **

## Joint Spectral Amplitude

**Joint Spectral Amplitude**

- Analytical Approximation

## How much entanglement? 

**Concurrence**

**Type-I SPDC **

**Type-II SPDC **

## How much entanglement? 

## Quantum Teleportation with Entangled Multimode Photons

## How good is it?

**How good is it?**

- Type I

- Type II

- Optimal input photon

## How good is it?

- No spectral correlation

**How good is it?**

## How good is it?

- Spectrally correlated

**How good is it?**

## How good is it?

**How good is it?**

## Review of Quantum Teleportation with Entangled Multimode Photons

**2007 IC Postdoctoral Research Fellowship Colloquium**

- Purpose:

- Quantify fidelity

- Quantify polarization entanglement

- Related Protocols:

- Entanglement Swapping

- Results:

- (Quantum Repeater)

- Fusion Gates and Cluster States

- (Quantum Computing)

- Optimize fidelity

- Characterize multimode effects in QT

- Quantum Key Distribution

- Contact Information

## Travis S. Humble
Oak Ridge National Laboratory
humblets@ornl.gov

- Oak Ridge National Laboratory
- humblets@ornl.gov

**Quantum Teleportation ****with Entangled Multimode Photons**

- PI: Warren Grice

- IC: Susan Durham

- _Agenda_

**Quantum Information and Teleportation**

**Entangled Multimode Photons**

**Teleportation with Multimode Photons**

**Communicating and Computing Applications**

**Sensing and Security Applications**

**2007 IC Postdoctoral Research Fellowship Colloquium**

**Notes:**
2007 IC Postdoctoral Research Fellowship Colloquium, 20 April 2007, Chantilly, VA

## Quantum Teleportation

**Notes:**
First, an analog to clarify the use of quantum teleportation.
A conventional fax machine transmits information, not paper, between two locations.
Similarly, teleportation transmits qubits of information, not matter.
Particle 1 stores the qubit initially. Particles 2 and 3 are entangled and will act like a quantum communication channel through which the qubit is transferred to particle 3.
To do this, particles 1 and 2 are subjected to a Bell-state measurement, which is a means of jointly measuring two particles.
If successful, particle 3 will be left in a state that is unitarily related to the initial qubit.
Here are the caveats. First, qubit stored in particle 3 is encrypted, and it is encrypted perfectly. In order to recover the information, we have to know the outcome of the Bell-state measurement, and that requires some classical information be sent from here to there. So in short, you don’t get something for nothing.
The second caveat, and why the analogy with a conventional fax machine fails, is that particle 1 now no longer stores any information. The qubit is gone, it is at particle 3. Hence the name teleportation.

## Entanglement Swapping

**Entanglement Swapping**

**Teleporting entanglement**

## Quantum Repeater

- Repetitive entanglement swapping

- Concurrence

## Entanglement Swapping

**Concurrence versus N**

**Equivalent bandwidths**

**Does not incorporate entanglement distillation**

## Fusion Gates and Cluster States

**Fusion Gates and Cluster States**

**type-I**
**fusion**

**Adding together entangled states**

**Linear**

**Branched**

**type-II**
**fusion**

## Fusion Gates and Cluster States

**Adding together entangled states**

***N***** particles**

***n*****=*****N*****/2 *****+*****1**

## Fusion Gates and Cluster States

- Concurrence versus N

- Equivalent bandwidths

**Same as entanglement swapping (for identical sources)**

## Review of Quantum Teleportation with Entangled Multimode Photons

**2007 IC Postdoctoral Research Fellowship Colloquium**

- Purpose:

- Quantify entanglement (concurrence)

- Entanglement swapping, type-I fusion

- Related Efforts:

- Quantum Repeater

- Results:

- Incorporate Distillation

- Optimize configurations

- Analyze protocols related to QT

- Building Quantum Networks

- Contact Information

- One-way quantum computing

- Architecture modeling