Quantum Memory For Teleportation And the Quantum Internet

transcript

Team:Ahmed Hasan (Undergrad Student)Ken Salit (Graduate Student)Jacob Morzinski (Graduate Student/MIT)Dr. Venkatesh Gopal (Post-Doc)Dr. Gaur Tripathi (Post-Doc)Prof. Philip Hemmer (Texas A&M: Visitor)

Supported By:ARO, ARDA

BASIC OBJECTIVES

Demonstrate A Quantum Memory Unit (QMU) In the Form of a Single Rb Atom Trapped Inside a High Finesse Cavity

Demonstrate Transfer of Photon Entanglement to a Pair Of QMU’s.

Demonstrate Quantum Teleportation via Measurement ofAll the Bell States

“Long Distance, Unconditional Teleportation of Atomic States Via Complete Bell State Measurements,” S. Lloyd, M.S. Shahriar, J.H. Shapiro and P.R. Hemmer, Phys. Rev. Letts.87, 167903 (2001)

TELEPORTATION: WHAT

EARTHALPHA-CENTAURI

| |BEFORE...

AFTER...

| |W||||

BELL STATES

DECOMPOSITION

||||||||

TELEPORTATION: VIA BELL STATE MEASUREMENT

| |W||||||||

| |-1 0

| |0 1

| |0 -1

LASER-CONTROLLED SPIN EXCITATION OFF-RESONANT

GOOD FOR SINGLE BIT OPERATION

(|A> + |B>)|+>=(|A> - |B>)|->=

LASER-CONTROLLED SPIN EXCITATION RESONANT

0EXPT. IN Rb TWO-PHOTON DETUNING

THE DARK STATE:: GENERAL CASE

|a> - |e> |b> - |e>

|a> + |e> |b> + |e>

|->=|b> |->=|a>

|+> - |e>

|+> + |e>

|-> = (2|a> - 1|b>)/|+> = (1|a> + 2|b>)/

ADIABATIC TRANSFER VIA THE DARK STATE

TOPOLGICALLY ROBUST

EQUIVALENT TO A -PULSE

ATOM A

ATOM B

COHERENCE TRANSFER VIA CAVITY QED

ATOM 1 ATOM 2

|a1> |b1>

|a2> |b2>

|a1 b2 0> |b1 a2 0>

1 g 2g

|b1 b2 1>

|e1 b2 0> |b1 e2 0>

2 g 1 g12

ONE CAVITY PHOTON

|b1 b2 0>

NO CAVITY PHOTONS

ADIABATIC COHERENCE TRANSFER VIA CAVITY-QED DARK STATE

||a1>|b1>) |b2> |0>

||b1 a2 0>|b1b20>) = |b1> |a2 >|b2>) |0>

ATOM B

ATOM A

ATOM B

TRANSFERRING TWO BITS INTO A SINGLE ATOM VIA CAVITY QED

TRANSFER PHOTON ENTANGLEMENT TO ATOMIC ENTANGLEMENT

EXPLICIT SCHEME IN 87RBC

ATOM 1 IN ARBITRARY STATE: TO BE TELEPORTED

|1> ={|c>1+|a>1}

ATOMS 2 AND 3 ARE FIRST ENTANGLED USING THE PHOTON-CAPTURE PROCESS

|23>={ |a>2|b>3 - |b>2|a>3}/2

COMPLETE STATES OF ALL THREE ATOMS

|1> ={|c>1+|a>1}

|23>={|a>2|b>3 - |b>2|a>3}/2a b

ATOM B

ATOM A

ATOM B

TRANSFERRING TWO BITS INTO A SINGLE ATOM VIA CAVITY QED

TRANSFER STATES OF 1 AND 2 INTO 2 ONLY

QUANTUM STATE AFTER THE TRANSFER

|1> ={|c>1+|a>1}

|23>={|a>2|b>3 - |b>2|a>3}/2

BEFORE TRANSFER

|A>={|c2>|b2>}/2, |B>={|d2>|a2>}/2.

|23>={|A+>(|b3>+|a3>) + |A->(|b3>-|a3>) + |B+>(|b3>+|a3>)+ | B->(-|b3>+|a3>)}/2

AFTER TRANSFER

|1> = |c>1

BELL STATES

ROTATE SUPERPOSITION-BASIS BELL STATES INTO PURE-BASIS BELL STATES

|A+>=|c2>+|b2> |A->=|c2>-|b2>|B+>=|d2>+|a2> |B->=|d2>-|a2>.

OLD BELL STATES

pulses

|a+>=|c2> |a->=|b2>|b+>=|d2> |b->=|a2>.

NEW BELL STATES

MEASURING BELL STATES VIA SEQUENTIAL ELIMINATION

THE QMU

FORT Beam

Cavity FieldRb Atom

THE MACHINERY

VALVEO

MAIN CHAMBER: UHV

LAUNCH BEAM: TSL1

UPPER CHAMBER: UHV

5S1/ 2

780.1 nm

Fig. 2

THE CAVITY AND THE FOUNTAIN

Launch laser beam

Pulsed ServoBeam

Pulsed Probe Beam

FORTBeam

Copper Block For Vibration Isolation

STABILIZING THE CHIRP

DIODELASER

DIFFERENTIATOR

MULTIPLIER DELAY PULSE GENERATOR

INTEGRATORADDER

LASERCONTROLLER

TOEXPERIMENT

ABSORPTION CELL

5S1/ 2

780.1 nm

Frequency Stabilization of an Extended Cavity Semiconductor Laser for Chirped Cooling,” J.A. Morzinsky, P.S. Bhatia, and M.S. Shahriar, to appear in Review of Scientific Instruments

REALIZING THE FOUNTAIN LAUNCH

LAUNCH BEAM: TSL1

Adjustableheight

To sat. abs.locking

To trap

Launch beam

Timers

on/off

Magneticfield

REALIZING THE FOUNTAIN LAUNCHLaunch Fluorescence, 2 mm Height

LAUNCH BEAM: TSL1

Adjustableheight

Magnetic field

Trap laser

Launch laser

300 ms

3 ms 100 ms

5 ms 100 ms

1 2 3 4 5 6 7 8 9

x 10-3

Time (sec.)

REALIZING THE FOUNTAIN LAUNCHLaunch Fluorescence, 10mm Height

LAUNCH BEAM: TSL1

Adjustableheight

Magnetic field

Trap laser

Launch laser

300 ms

3 ms 100 ms

5 ms 100 ms

1 2 3 4 5 6 7 8 9

x 10-3

Time (sec.)

REALIZING THE FORT IN-SITU

5S1/ 2

780.1 nm

Fig. 2

TSL3IMAGE INTENSIFIEDCCD CAMERA

782.1 nm

IMAGE INTENSIFIEDCCD CAMERA

FIBER FORT

20 msec

REALIZING THE HIGH-Q CAVITY

STABILIZING THE HIGH-Q CAVITY

THE NEW CAVITY : SIDE VIEW

THE NEW CAVITY : TOP VIEW

FORT beam input port

Cavity beamoutput port

Cavity mirrorholder

THE NEW CAVITY : INTERNAL DETAILS

OFR FT-51x76

Cavity beam output

FORT beam input

Cavity beaminput

PLAN FOR MAGNETICALLY GUIDED FOUNTAIN FOR QMU

LAUNCH BEAM: TSL1

TSL3F'

5S1/ 2

780.1 nm

Fig. 2

810 nm

MagneticallyGuided Fountain

0.7 NA Mic. Objective

Im. Int. CCD

PUBLICATIONS AND PUBLICITY

“Long Distance, Unconditional Teleportation of Atomic States Via Complete Bell State Measurements,” S. Lloyd, M.S. Shahriar, J.H. Shapiro and P.R. Hemmer, Phys. Rev. Letts.87, 167903 (2001)

Frequency Stabilization of an Extended Cavity Semiconductor Laser for Chirped Cooling,” J.A. Morzinsky, P.S. Bhatia, and M.S. Shahriar, to appear in Review of Scientific Instruments

“Observation of Ultraslow and Stored Light Pulses in a Solid,” A. V. Turukhin, V.S. Sudarshanam, M.S. Shahriar, J.A. Musser, B.S. Ham, and P.R. Hemmer, Phys. Rev. Lett. 88, 023602 (2002).

“Determination Of The Phase Of An Electromagnetic Field Via Incoherent Detection Of Fluorescence,” M.S. Shahriar, P. Pradhan, and J. Morzinski , submitted to Phys. Rev. Letts. (quant-ph/0205120).

Cavity Dark State for Quantum Computing,” M.S. Shahriar, J. Bowers, S. Lloyd, P.R. Hemmer, and P.S. Bhatia, Opt. Commun. 195, 5-6 (2001

“Physical limits to clock synchronization,” V. Giovannetti, S. Lloyd, L. Maccone, and M.S. Shahriar, Phys. Rev. A 65, 062319 (2002)

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Quantum Memory For Teleportation And the Quantum Internet

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