Hypersonic matterwave guiding for atom-interferometry

Hypersonic matterwave guiding
 for atom-interferometry

Wolf von Klitzing

Atomtronics @ Benasque 08/08/2019

FORTH—IESL

ESA-OBST1 ESA-OBST2

MatterWave

Marie Curie-Excellence 
 MatterWaves

Marie Curie-Excellence 
 Fellowship

QUESCA

FORTH

Vasiliki Bolpasi Georgios Vasilakis Konstantinos Poulios

Wolf von Klitzing Saurabh Pandey

Hector Mas

Giannis Drougakis

Premjith Thekkeppatt

BEC in Space:

Testing Einstein’s Weak equivalence

principle STE-QUE

ST

Guided for Matter-Wave Interferometry for inertial navigation

Matter ^-Wave Interferometry

7 23 34

C C

Matter-Wave&Quantum Tools

120327_ 1335_ 35

Ultra-Bright Atom Lasers

BEC and MatterWaves at ^IESL-FORTH

Very long Baseline

Matterwave interferometry

ELGAR SAGE

Large

Interferometers

AtomQ T ^.eu

Short-term visits…

1 week - 2 months

for experimentalists and theorists

AtomQT

To the lab

S. Pandey, G. Drougakis, K. Mavrakis, P. Christodoulou, K. Poulios, I. Alonso-Miguel H. Mas, W. von Klitzing, V. Bolpasi

G. Vasilakis

M. Mikis For open PhD and Postdoc Positions see BEC.gr

S. Pandey, G. Drougakis, K. Mavrakis, P. Christodoulou, K. Poulios, I. Alonso-Miguel H. Mas, W. von Klitzing, V. Bolpasi

G. Vasilakis

M. Mikis For open PhD and Postdoc Positions see BEC.gr

ϕ = 1

ℏ ∫ ( U ₂ ( t ) − U ₁ ( t ) ) dt

= 1.5  rad / feV in 1s

Matterwave

Interferometry

= 13  rad / nm in 1s

Bloch Lab

8 m

Free Space

Stanford / Wuhan / Hannover

700 km

Outer Space

STE-QUEST


Matter-Wave Interferometers

ELGAR


ZARM

drop Tower

120 m

NASA CAL

ESA

C-COOL

Free Fall

JO URN AL OFM OD ERN OPTI

CS 3

Figure3. Ionchip

producedat Ben-GurionUniversity

before Springer Twoions Schmidt-Kaler Mainz.Inset: Ferdinand permissionfrom of 1),with chamberat Courtesy from( chip. thevacuum the adapted on installationin trapped (Mainz)and Science+BusinessMedia.

hybriddevices (54

),superconductors (55

–58 ),exotic

ma- –67 (64 –63),double- fromJohnson 59 modes( affectingeverything atter-waveinterferometry andvacuum andm CPforces ndgeometries terialsa noiseto wellpotentials

), of tor 71), ons brief – ses ula circuits bos 73).The (69 im rangeof leu Whilethe ral as ssib eut fterthis of epo ten ist thewide superflow( fth sta ons inmesoscopic atomchips. so follows:a nd- sc ple 68),atomtronics as ple rou chips. am g( ofbosonic focuseson forg exam pin dex usedwith 2 ofelectrons atom sha ned goo ore on lan are om isstructured arenow ep pulse ics Tw wer top ave theinvestigation on. ips -w ree so uantumpumping ter )and tch Thispaper tth mat and forq (72 las tunnellingbarriers introduction,Section particlesthat firs , - c nd tri po- and first ma- chip pro- dro chips room arbon mainly urrent- elec ave ihy starting materials alsobeing ant for row ithc the chamberhas anatom ).We trapand des and chipsfor Whilethe mic nowbeing withatom 79 ignificantlya impressivework , tro ofexotic again, nanowires,c . ons and molecules,ions lec (78 surfacew vacuum use ),nor sitr ,e BEC ncy na exampleof chipsare ets withatom ,po –77 where, designedto the iversifieds que make 74 agn ons on.The fre sis uperconductorsare Atom thetechnology. basedo been rot aved io- well( ent ntm notdeal vapouralthough tip existto rad andso presentsan rim ane atoms,fermions, 3 heyh gan rystallinematerials, eutralatoms for ‘atom-like’systems hereas erm coldions. expe pin as dealswith photonics.S havesince igure weremainly ep ires,t 3 oldn ost Proposals rap enn reviewdoes alloys,c lud nc fm ant fort eendone inc ed nto ds, Section atomchips nipulateRydberg electrons.F operatedwith pos gen.Our temperatureatomic hasb forsolid-state focuso poi atomchips carryingw now fiel tentialsand usednow. suchas nanotubes(CNTs)

alsoevolved.

Someatom chipsare

utilizedas

afacet holdsthe acuumwithin thev thesubstrate suchthat chipshave theratom chamberitself ofthe vacuum.O the itie cav thevision havewithin and electricfield des pumps),particle and dio hichwill oto stepstowards iaph chipw magnetic tsv atom dou acuum(including rea areimportant ownv ted sourcesand its gra nte s.I fullyself-contained rce substrate.These ofa thesubstrate sources,light sou s n 5. es as ls, he by ne- tio such have these chips rapid nt eria forc atom- well orfab- sources men chipand de optics,it chipwas wee as mat processing limitations atom perspective. clu itly bet inSection interferome- on Weapologize ofelectronics fieldof honour perspectivesin adepossible chipsfor atom sin ts ns plic tonoise to thehypothesized applications althoughwe theatom igh ion inmaterial ctio eex describe yway aveinadvertently act ins nascent pticsm tw progressin era that, ofatom hilethe also ter int tha andtrapped interferometers effectsas inorder moreintimate formatter-wave chipb new mayh that we remarksand manyof interferometry ein effectsdue ch on ote forthe hatw ide the on theuse hes additionalpeople. sn nd rsu Here cus quantuminformation imperfections abase atter-waveo escribepotential isdone prov e.T etu e,a wholed to esfo availablea weexpect efforts,we efo fm t,l 1). to ed fac coursepossible forc rch eas wefocus sur 4,w BECs. Mach–Zehnder 6,w emphasizet sea serveas used CP otl alsodiscuss isof free-space,guided someconcluding tomake the ofthose (Figure sensorsand mentionsome newpossibilities be addition, he and chipsdue fforts.This exampleo utn 7. Johnsonnoise. nd suchoversights. transmittedfrom st tb es, also tomchip, ha fac msa InSection Asan InSection Wegive Las willbe andfibres ato suc suchas ofatom rication.We designedto may sur fifthforce. thea Wediscuss try,including Sagnacs. asclocks, (QIP).In willopen tronics.We productionof Section thenames relatede peopleand However,it madeconsiderable glectedto forany

2.Chip-trappable species

In its earli

est day

s,t he ato mc

hip was

use dfo rth

ec

on- oso lb tra neu te sta nd- grou of ion lat ipu man nd la tro

ns ydberg choice. ofatom areeven muchwider morerecent osonsof Rb, ₈₇ includingR theb Atomchips includea yis theworkhorse log hno tec truethat eutralparticles, expandedto metalsWERE nd andmolecules. sa ent tremains im thealkali ultracoldn per pex only,and Althoughi chi developmentshave rangeof atoms,fermions

Downloaded by [FORTH] at 06:53 30 May 2016

JOURNAL OF MODERN OPTICS 3

Figure 3. Ion chip produced at Ben-Gurion University before

installation in the vacuum chamber at Mainz. Inset: Two ions trapped on the chip. Courtesy of Ferdinand Schmidt-Kaler (Mainz) and adapted from (1), with permission from Springer Science+Business Media.

hybrid devices (54), superconductors (55–58), exotic ma- terials and geometries affecting everything from Johnson noise to CP forces and vacuum modes (59–63), double-

well potentials and matter-wave interferometry (64–67),

matter-wave pulse shaping (68), atomtronics (69–71), and so on. Two more examples consist of a simulator for quantum pumping of electrons in mesoscopic circuits (72) and the investigation of bosonic superflow (73). The last three topics are good examples of the possible uses of tunnelling barriers on atom chips.

This paper is structured as follows: after this brief

introduction, Section 2 focuses on the wide range of

particles that are now used with atom chips. While the first chips were planned for ground-state neutral bosons, atom chips have since been designed to trap and ma- nipulate Rydberg atoms, fermions, molecules, ions and

electrons. Figure 3 presents an example of an atom chip

operated with cold ions. Atom chips are now being pro- posed for trapping antiprotons, positrons and antihydro- gen. Our review does not deal with atom chips for room temperature atomic vapour although impressive work

has been done here as well (74–77), nor with atom chips

for solid-state ‘atom-like’ systems (78, 79). We mainly

focus on cold neutral atoms where, again, the starting point of most experiments is the BEC.

Section 3 deals with the technology. While the first

atom chips were mainly based on a surface with current- carrying wires, they have diversified significantly and now include permanent magnets, electrodes for electric fields, antennas for radio-frequency and microwave po- tentials and photonics. Superconductors are also being used now. Proposals exist to make use of exotic materials such as alloys, crystalline materials, nanowires, carbon nanotubes (CNTs) and so on. The vacuum chamber has

also evolved. Some atom chips are utilized as a facet of the chamber itself such that the substrate holds the vacuum. Other atom chips have the vacuum within the substrate. These are important steps towards the vision of a fully self-contained atom chip which will have within the substrate its own vacuum (including pumps), particle sources, light sources and magnetic and electric field sources. Integrated readouts via photodiodes and cavities will be transmitted from the chip by way of electronics

and fibres (Figure 1).

In Section 4, we focus on interactions between the

atoms and the surface. These interactions include forces such as the CP force, and effects due to noise sources such as Johnson noise. Here we also describe limitations of atom chips due to imperfections in material or fab- rication. We emphasize that while the atom chip was designed to serve as a base for matter-wave optics, it may also be used to provide new insights on materials, surfaces, and searches for such effects as the hypothesized fifth force.

As an example of matter-wave optics made possible by

the atom chip, we focus on interferometry in Section 5.

We discuss free-space, guided and trapped interferome- try, including Mach–Zehnder interferometers as well as Sagnacs.

In Section 6, we describe potential applications such

as clocks, sensors and quantum information processing (QIP). In addition, we expect that progress in atom chips will open new possibilities for the nascent field of atom- tronics. We also discuss the use of atom chips for rapid production of BECs.

We give some concluding remarks and perspectives in

Section 7.

Last but not least, let us note that we explicitly mention the names of those who led many of the atom chip and related efforts. This is done in order to honour these people and to make available a more intimate perspective.

However, it is of course possible that, although we have made considerable efforts, we may have inadvertently ne- glected to mention some additional people. We apologize for any such oversights.

2. Chip-trappable species

In its earliest days, the atom chip was used for the con- trol and manipulation of ground-state neutral bosons only, and the alkali metals WERE the bosons of choice.

Although it remains true that the workhorse of atom

chip experiments and technology is ⁸⁷Rb , more recent

developments have expanded to include a much wider range of ultracold neutral particles, including Rydberg atoms, fermions and molecules. Atom chips are even

Downloaded by [FORTH] at 06:53 30 May 2016

im aging

a BEC

in the

Siem

ens

star

pattern,

we

find

a M TF

FWHM

of 0.71

! 0.02

" lp ∕ μ m , correspo

nding

to a PSF

FWHM

of 1250(20)

nm,

larger

than

the 960(8

0) nm

single-mirror

im age

at 780

nm

illumination.

We

believe

that

this

∼ 30%

increase is

consistent

with

atom

diffusion

due

to photon

recoil

during

the

10 μ s repump

and

resonant

imag

ing

pulse

[ 40 ].

Fig.

4.

DMD-patterned

optical

traps

and

resulting

resonant

absorption

images

of atom

distributions.

Atoms

are repelled

from

bright

regions

of the

projected

pattern,

which

is the inverse

of the binar

y image

applied

to the DMD.

We

image

the atoms

immediately

after

turning

off the optical

trapping

potentials,

with

a magnification

of 52.6

× . Bright

areas

represent

regions

of high

atomic

density

and

OD.

(a) Ring-trap

potential

from

a single

exper-

imental

realization.

TOF

analysis

gives

N # 1.3

× 10

5 atoms

with

matter

– wave

interference

leading

to the appearance

of a central

peak

[ 39 ]. (b) Lattice

pattern

produced

by applying

a Floyd

– Steinberg

error-diffusion

algorithm

[ 31 ] to

an 8 bit image

of a sinusoidal

lattice

with

10 μ m period,

sho wn with a

single

realization

of a BEC;

N # 3.7

× 10

5 and

the BEC

fraction

is 34%.

This

image

was

produced

by leaving

the magnetic

trap

on,

resulting

in ω ^r #

2 π × 20

Hz

harmonic

radial

confinement.

(c) Checkerboar

d pattern

applied

to the atoms,

imaged

with

a single

shot.

Addi

tional

evaporation

after

transfer

to the all-optical

trap

results

in a nearly

pure

BEC

in TOF

with

N # 2.4

× 10

5 atoms.

(d) Ring

lattice

of 25 sites,

with

ring

radius

of 43.2

μ m, and

site

radius

of 4.32

μ m, with

N # 3.16

× 10

5 atoms.

(e) Artistic

impressions

of Bose

and

Einstein

applied

to a nearly

pure

BEC

of N # 5.2

× 10

5 atoms,

averaged

over

five

experimental

runs.

ODs

abov

e ∼ 2.5

are belo

w the signal-to-noise

threshold

of the horizontal

imaging,

leading

to slight

undercounting

of the

atoms

in this

case.

Einstein

image

from

www

.muraldecal.com

, used

with

permission.

Research

Artic le

Vol.

3, No.

10 / October

2016

/ Optica

1140

Atomtronics

Y. J. Wang et al. Phys.Rev.Lett 94: 090405 (2005) G. Gauthier et al. Optica 3:10 1136 (2016)

K. Henderson et al. N. J. Phys. 11: 043030 (2009)

Mark Keil et al. Journal of Modern Optics : 1-46 (2016)

Atomtronics Wave Guides

Boshier C riteria of Atomtronics

• L _oop

• S _mooth

• D _ynamic

• Dipole Traps

- Guides - Lattices

- Paintings - Fibres

LSD LSD LSD LSD - TAAPs

LSD

• Magnetic Fields

- IP-Trap

- Atomic chips - Mini-traps

- Adiabatic (LSD) LSD

LSD LSD LSD

Time-A veraged


Adiabatic Potentials .

Benasque 2015 ?

A k ( ) , z ^{∝ exp} ( ) ^{− kz kz}

For kz ≫ 1

Jones, et al. J. Phys. B 37, L15 (2004)

Gauthier et al. Optica 3:10 1136 (2016) Y. J. Wang et al. PRL 94: 090405 (2005)

A k ( ) , z ^{∝ exp} ( ) ^{− kz kz ≈ 10 − 275}

For kz = 2 π

0.5mm × 50mm ! 630

Topology

10 ^{− 1}

10 ⁴ 10 ⁰

10 ⁶ 10 ¹⁰ 10 ¹⁴

Experiment Repetition

Quasi DC

Manipulation

Time

Averaging

Adiabatic (Dressing)

Hyperfine Transitions

Trapping &

Detection

Atomtronic Time Scales ^{@ Crete}

Frequen cy [Hz]

ω ^Trap ω ^Larmor

Quasi Static

~ DC

Time-

Averaging

Audio

Adiabatic
 Potentials

RF

Time averaged Adiabatic Averaged Potentials

(TAAP)

Gravity

Adiabatic Potentials


TAAP

Time-Averaged


(TAAP)

3 × 10 ^{− 275}

Suppression of

roughness by

BEC in a Ring

1) MOT

2) Quadrupole-Trap

3) BEC in Dipole Trap

4) BEC in Ring

BEC in a Ring

1) MOT

2) Quadrupole-Trap 3) BEC in Dipole Trap 4) BEC in Ring

5) Accelerate

Bang-Bang Scheme of Optimal Control Theory

Chen et al. Phys. Rev. A 84, 43415 (2011).

0.00 0.05 0.10 0.15 0

50 100 150 200 250 300 350

Acceleration time [ s]

ϕ [ deg ]

2π 25rad /s

²

2π 50rad/s

²

2π 400rad/s

²

2π 200rad/s

²

2π 100rad/s

²

Angular Position [deg]

Acceleration time [s]

Acceleration of BECs in TAAP rings

using the bang-bang scheme of optimal control theory

Chen et al. Phys. Rev. A 84, 43415 (2011).

0 1 2 3 4 5 6 7 3.0

3.2 3.4 3.6 3.8

Ring hold [s]

Cloud P osit ion [ mm ]

BEC Guiding at 10Hz

nlm ( vara )

T = 113 nK

v = Mach 16

Hypersonic BEC 


in an accelerator ring

v = 30 mm/s v _c = μ / m

S. Pandey et al. Nature, in press

No extra

heating !

Expansion of a rotating BEC in the ring

Ring Accelerator

Effective Flatness of the waveguide: 


189 pK = 2 nm

Ring Accelerator

80 000 atoms with 40 000 / atom !

~ 1 mm

Static vs Supersonic atoms

g)

1mm

a)

1mm

Flatness < 250 nK Flatness < 189 pK

Optimal Control
 Atom-Optics

Free expansion Delta Kick

2 nK 48 nK

Optimal Control
 Atom-Optics

Free expansion Delta Kick

Loading Rotating BECs in to a Shell

BECs in a shell at 50nK

Adiabatic!

A m p li tu d e o f o s c il la ti o n s [ μ m]

Duration of Transfer [ms]

Hold Time [s]

Radius [ μ m]

• Matterwave accelerator ring

• Lossless Hypersonic flow of BECs

• Optimal Control

• Ultra-high angular Momentum

• Atomtronics (Delta-Kick)

• State dependent control of 
 multi-component BECs

Summary

BEC rings


!

40000

-1×10⁷ -5×10⁶ 0 5×10⁶ 1×10⁷

0 100 000 200 000 300 000 400 000 500 000

mw det [Hz]

atomnumberF=2

Atomtronic Ring Physics

P andey et al @ Na tur e 2019