Quantum Interference and Imaginglsl.postech.ac.kr/data/con20_06.pdf · 2020-07-06 · Quantum...

Battle 2 - Quantum Interference and ImagingQuantum Battles 2020

Quantum Interference and Imaging

Kasra AminiThe Institute of Photonics Sciences, ICFO, Spain (J. Biegert group)

Alexis ChaconMax Planck Research-Initiative, MPK & POSTECH, Korea (D. E. Kim Director)

Sebastian Eckart Goethe-Universität Frankfurt, Germany (R. Dörner group)

Benjamin Fetić University of Sarajevo, Department of Physics, Bosnia and Herzegovina (D. B. Milosević group)

Matthias Kübel Friedrich Schiller University Jena, Germany (G. G. Paulus group)

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Outline of Quantum Battle 2: Quantum Interference and Imaging

• B1 – Interference is a mathematical trick (it is not real). All that can be measured is intensity or

• B2 – How are LIED and holography useful to measure molecular structure?

• B3 – All can be learned by just solving the TDSE. Why do experiments?

• B4 – No one should ever solve the TDSE.

• Open discussion - Decoherence is a symptom of an incomplete measurement and has no physical reality.

|𝜓 2 .

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B1 – BenjaminInterference is a mathematical trick (it is not real).

All that can be measured is intensity or |𝜓 2

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P. Bucksbaum et al., J. Opt. Soc. Am. B 4, 760 (1987)

𝐸kin = 𝑛ℏ𝜔𝐼𝑅 − 𝐼𝑃 − 𝑈𝑃

ℏ𝜔𝐼𝑅 = 1.16𝑒V

𝐼𝑝(𝑋𝑒)

ℏ𝜔XUV = 19 ⋅ ℏ𝜔𝐼𝑅

𝜆 = 56 𝑛𝑚

Quantisation in strong fields: ATI in Xe - Benjamin

Photon picture is a successful model for

the fundamental strong-field effects

Up ∝ I0λ2

L. V. Keldysh et al., Sov. Phys. JETP 20, 1307 (1965)

Figure adapted from K. Amini, D.Phil thesis, University of Oxford (2017)

K. Amini et al., Rep. Prog. Phys. 82, 116001 (2019)

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If somewhere is written “interference” this simply indicates that the author was incapable of identifying the conserved quantity of the

system.

Example: Angular positions of the interference maxima for the double slit:

! The conserved quantity for the double slit

is one “doubleslititron” and has the value

𝜃𝑛 = 𝑛 ⋅𝜆𝑑

𝜆𝑑

Hypothesis: We don’t need no interference - Matthias

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Battle 2 - Quantum Interference and ImagingQuantum Battles 2020 �6


Propositions:(1) the ground state (GS) is the e-wave packet source (2) the laser-GS interaction can create multiple time-space slits (Sn) (3) the slits are located about zero of the electric field at tn, let’s assume an approximated time-window of T0/5 (4) by symmetry argument, these slits are separated by a laser-cycle T0 (5) the final energy distribution will be given by the squared of the sum of the individual EWPs produced by each slits

Sn: � with � 𝑃 (𝜀𝐤, 𝑡F) = |∑

𝑛

𝑎𝑛(𝜀𝐤, 𝑡𝑛, 𝑡F) |2 𝑎𝑛(𝜀𝐤, 𝑡𝑛, 𝑡F) = 𝐴𝑛( ⋅ )𝑒−𝑖𝑆(𝜀𝐤,𝑡𝑛,𝑡F)

Electron GS-GUN

S1 S2 S3 S4

Measured Final photoelectron Spectrum

EL(t)

Direct ATI and ultrafast slits analogy - Alexis

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ATI peaks can be explained as an inter-cycle interference or by using

energy conservation

!What about other types of interference?

Matthias

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Sub-cycle electron trajectories - Kasra

F. H. M. Faisal, Nat. Phys. 5, 319 (2009)

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Y. Huisman, et al., Science 331, 61 (2011) (SOM)

ATI “Temporal Double Slit“ Strong-field PE holography

Intracycle Interference

Scattering-free Interference

signalreference Δ𝜙

Propagation in ionic field

Emission time difference

direct

rescatteringlong

short

Types of interferences & holography - Matthias

Spacing in time gives the interference fringes in momentum space; space in time equals to photon energy

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Intra-cycle interference cannot be modeled by photons - Sebastian

0

Ey [

arb.

uni

ts.]

-1 0 1-1

1

Ex [arb. units.]

0

py [

a.u.

]-1 0 1

-1

1

px [a.u.]

Han, M., Ge, P., Shao, Y., Gong, Q. & Liu, Y., Phys. Rev. Lett. 120, 73202 (2018) Feng, Y. et al., Phys. Rev. A 100, 63411 (2019)

Eckart, S., Preprint at https://arxiv.org/abs/2003.07249 (2020)Trabert, D. et al. Preprint at https://arxiv.org/abs/2005.09584 (2020)Eckart, S. et al. Preprint at https://arxiv.org/abs/2005.04148 (2020)

How can position-information or time-information be retrieved from measured electron momentum distribution without recolisions?

Sub-cycle interference allows for the retrieval of e.g.:! complex valued electron continuum wavefunction

! position offset of the electron wave packet at the tunnel exit ! Wigner-time delay in the molecular frame

First, Intra-cycle interference cannot be modeled by photons, because the time scale needed to explain intra-cycle interference Tintra is below one cycle of the light field. ! The concept “photon” does not exit on sub-cycle time-scales.

Second, this also indicates that the wave-particle duality is nonsense on sub-cycle time-scales.

Poll: - A) Photons do not exist at all - B) Photons cannot be used to model physics on sub-cycle time scales (t<1/Eph) - C) Photons are just as good as time dependent fields to model physics (wave particle duality)

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➡ Single Attosecond EWP

➡ How to recover the phase, if the measurement |ap|^2 lost it 😿 ?

XUV-Attosecond pulse

Atom

e-

📷 EWP

EWP Amplitude

EWP Phase

A. Chacon et al., PRA 87, 023408 (2013)

Attosecond electron wave packet (EWP) measurement - Alexis

Remetter et al., Nature Phys. (2006)

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|ap|^2 => |ψp|^2


💡 What about analogies? Instances, electromagnetic-laser interferometry tech, i.e. SPIDER

💡 But now with EWPs? https://www2.physics.ox.ac.uk/research/ultrafast-quantum-optics-and-optical-metrology/

How is the EWP-phase recovered if its phase is lost in Meas.? - Alexis


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But, but, … what about to recovering the wave-function? Still from EWPs’ interferences the dipoles or bound states are missing in Remetter’s paper!


EWP interferometry by Remetter - Alexis

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How to extract dipole structural information?

EWP1 EWP2

QSPIDER: Phase Interferometry for Direct EWP Reconstruction - Alexis

A. Chacon et al., PRA (2014)

Primises:

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Applications of qspider to retrieve EWPs And Dipole “phases":

SFA- ionisation from 2pz states of He+

A. Chacon et al., PRA (2014)

EWP-retrieval Dipole Matrix Element reconstruction

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QSPIDER: Phase Interferometry for Direct EWP Reconstruction - Alexis


Atomic Molecular

Strong-field holography

signal

reference

Laser-induced electron diffraction (LIED)

B2 – How are LIED and holography useful to measure molecular structure? - Benjamin

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LIED: quantum picture - Kasra

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Holography measures the electron wave packet - Matthias

�19M. Meckel et al., Nat. Phys. 10, 592 (2014)

Conclusion: “In our experiment, electron holography provides information about the continuum electron wave packet rather than the scattering object”

Off-center fringe pattern: what does it mean?


Image orbitals without rescattering - Matthias

M. Meckel et al., Science 320, 1478 (2008)

3p, |m| = 1

3p, m = 0

M. Kübel, et al., Nat. Commun. 10, 1042 (2019)

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LIED works! - KasraMIR-LIED of C2H2

+

M. Pullen et al., Nat. Commun. 6, 7262 (2015)

C. I. Blaga et al., Nature 483, 194 (2012). B. Wolter et al., Science 354, 308 (2016)

MIR-LIED of C2H22+

deprotonation

LIED

CED (IAM)

NIR-LIED of N2+

Time after ionization (fs)

𝑝𝑟 = 𝑝∥ − A𝑟

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Conditions for LIED - KasraNIR-Scattering: Orbital structure retrieval

- Sensitive to valence electron cloud

- Too low Up and narrow momentum transfer range for molecular structure retrieval

- Boundary of quasistatic (tunnelling) regime- Ionization saturation; easily ionize and fragment large molecules with small Ip

K. Amini, J. Biegert, AAMOP vol. 69, Elsevier (2020). https://bit.ly/31qEOdRB. Wolter et al., PRX 5, 021034 (2015)

F. Schell et al., Sci. Adv. 4, eaap8148 (2018)

MIR-LIED: Molecular structural retrieval

- Large Up – avoid influence/blurring of valence electron cloud- Large momentum transfer range and small λdB – spatial resolution

- Avoid ionization saturation

- Deep into quasistatic (tunneling) regime – you can use classical models and map classical trajectories to exp. data

- Large EWP extent (x)

- Coincidence single molecule imaging

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Sebastian

B3 – All can be learned by just solving the TDSE.

Why do experiments?

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� 𝑖𝜕

𝜕𝑡 Ψ = − [ 1

2∆ +

1𝑟

+→𝐸 ⋅ →𝑟 ]Ψ

A short story of attoseconds - Matthias

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The end.


Example: Attoclock in atomic hydrogen - Matthias

U. S. Sainadh, et al., Nature 568, 75 (2019)

See also (original work in He, 𝛥tD < 34 as):

P. Eckle, et al., Science 322, 1525 (2008)

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Solutions for N>2, K>2 is very challenging to find

Hamiltonian of any molecule - Alexis

New review: P. Wustelt, M. Kübel, G. G. Paulus, and A. M. Sayler, AAMOP vol. 69, pp. 67–162.

Bromochlorofluoromethane

Alternative: DFT and TD-DFT

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We can measure this! - Kasra

M. Pitzer, M. Kunitski, A. S. Johnson, T. Jahnke, H. Sann, F. Sturm, L. Ph. H. Schmidt, H. Schmidt-Böcking, R. Dörner, J. Stohner, J. Kiedrowski, M. Reggelin, S. Marquardt, A. Schießer, R. Berger, M. S. SchöfflerDirect Determination of Absolute Molecular Stereochemistry in Gas Phase by Coulomb Explosion ImagingScience, 341 (2013) 1096

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(Semi-) classical model

TDSE vs (semi-) classical - Benjamin

TDSE Ψ(𝑡 → ∞)Ψ(𝑡 = 0)

𝐸(𝑡)

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B4.

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Example: Attoclock in atomic hydrogen - Sebastian

U. S. Sainadh, et al., Nature 568, 75 (2019)

See also (original work in He, 𝛥tD < 34 as):

P. Eckle, et al., Science 322, 1525 (2008)

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Reality is described by classical observables - Kasra

What we measure are intensities or • Electrons • Ions • Photons

Alternative interpretations of QM?

|𝜓 2

Poll: - A) Phases can be measured in the lab - B) Only can be measured in the lab - C) Quantum effects can be measured directly by looking at classical observables

|𝜓 2

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Extracting PES from time-dependent wave function - Benjamin

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PCS vs WO for hydrogen atom - Benjamin

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PCS vs WO for Argon atom - Benjamin

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Conclusion - Benjamin

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Kasra

Decoherence is a symptom of an incomplete measurement and has no physical reality.

Poll: - A) Agree - B) Disagree - C) I am not sure (I am a cat - maybe)

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Experiment: - dissociation of a neon dimer in a circularly polarized strong laser field- detect electron and ion in coincidence

Is the neon dimer decoherent? - Sebastian

M. Kunitski, N. Eicke, P. Huber, J. Köhler, S. Zeller, J. Voigtsberger, N. Schlott, K. Henrichs, H. Sann , F. Trinter, L. Ph.H. Schmidt, A. Kalinin, M. S. Schöffler, T. Jahnke, M. Lein, R. Dörner, Nat. Commun., 10, 1 (2019)

electron momentum distribution

in the polarization plane (in the molecular frame)

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electron momentum distribution

in the polarization plane (in the molecular frame)

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Option B: Interference in momentum space can be used to infer position-information regarding the molecule


! Interference is recovered selecting only one channel (knowing if an additional photon is absorbed or not) ! Decoherence is a symptom of an incomplete measurement and has no physical reality

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Some processes are incoherent by nature - Matthias

• Quantum physics is microscopic and coherent

• Experiments integrate over the macroscopic focal volume

Focal intensity distribution 𝐼(→𝑟 ) Focal phase distribution 𝜙0(→𝑟 )

D. Hoff, et al., Nature Phys. 13, 947–951 (2017)

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Coherence and incoherence in strong fields - Matthias

HHG: Phase matching coherent sum over Vfocus

𝒀 focusHHG =

∭𝑉

𝒀 atomHHG𝑒−𝑖𝜙(→𝑟 )𝑑3→𝑟

2

𝒀 focusATI =

∭𝑉

𝑌 atomATI 𝑑3→𝑟

ATI: Focal volume averaging incoherent sum over Vfocus

Poll: In HHG all atoms in the focal volume radiate coherently. On the other hand in ATI, electron emission from different atoms…

- A) Is inherently incoherent - B) Is coherent, but we cannot observe the coherence - C) I am not sure (I am a cat - maybe)

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Decoherence - Sebastian

Hackermüller, L., Hornberger, K., Brezger, B. et al. Decoherence of matter waves by thermal emission of radiation. Nature 427, 711–714 (2004)

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Decoherence - Sebastian

Akoury, Dominique, et al. "The simplest double slit: interference and entanglement in double photoionization of H2." Science 318.5852 (2007): 949-952.

E1 ≈ 110 eVE2 < 1 eV

Eγ = 160 eV E1 ≈ 85 to 105 eV

Eγ = 160 eV

5 eV < E2 < 25 eV“Decoherence is the loss of coherence of a quantum system caused by ignoring (i.e., tracing over) degrees of freedom to which the system is coupled and which are regarded as of no interest. The latter is termed the bath, although it need not be larger than one degree of freedom.”

Heekyung Han and Paul Brumer 2007 J. Phys. B: At. Mol. Opt. Phys. 40 S209

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Semiconductor occup dynamics HHG Spectrum 1D

Band-gap

Max

. ene

rgy-

gap

cv

Extending ultrafast science for electron structural and dynamics in condensed matter phases: Transition metal dicholoeidal Topological Chern insulators Topological insulators Weyl semimental Strongly-correlated materials ….

F. Langer, et al Nat. (2018)

TMDC Topological materials

Conducting edge states

Insulating bulk states

A. Chacon et al (2019) ArXiv Topo. Phase T. In Haldane Model

Future perspectives: dynamics in trivial and topological materials - Alexis

D. Bauer and K. K. Hansen. PRL (2018) R. Silva et al Nat. Photonics (2019) HHG in Haldane Model

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High harmonic in 3D topological insulators Bi2Se3

D. Baykusheva, A. Chacon et al. (in revision process)

S. Ghimire, D. Reis & T. Heinz SLAC California-USA

Topological anomalous Harmonic vs the ellip. Driven by 7.5 um Laser sources

Bi2Se3

3D TIs: - Insulating bulk bands - Conducting at the surface bands (protected by Time-reversal symm.)

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Towards the ultrafast e-h interferometry spectroscopy in trivial and topological materials?

Topological

D. Kim, H. Kang, D.E. Kim and A. Chacon (prelimirary results)

Trivial

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Acknowledgements

CANTON SARAJEVOMinistry for Education, Science and Youth

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– Quantum Interference Imaging Team: Kasra, Alexis, Sebastian, Benjamin and Matthias

Thank you for your attention and

don’t forget to see the world from other point of view

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