Post on 21-Aug-2020
Quantum Optics and Atomic Physics
NBI PhD afternoon 2016
Karsten Dideriksen
QUANTOP
Precision Measurements with Atoms and Molecules
– Current projects
Cavity QED for atomic clocks:
Spectrally ultra-narrow laser
sources
Aims and objectives:
Collective physics in cavities
Generating ultra-narrow laser
Superradiant laser sources
Compact molecular clocks
Strontium-88
Molecules
Precision Measurements with Atoms and Molecules
– Recent results
B. T. R. Christensen et al., PRA 92, 053820 (2015)
Atomic phase-response
signal for laser locking
Collectively enhanced atomic
emission
Theoretical Quantum Optics
Theoretical Quantum Optics
Quantum Information in practice
• Atoms
• Ions
• Superconducting qubits
• Cavities
• Quantum dots
• Photons
• All work is in close collaboration with experimental groupsaround the world
Any system that we think will work
Come join the QuantumInformation course
in block 4
Quantum Photonics
Quantum Dots – Solid State Artificial Atoms
Lodahl, Mahmoodian & Stobbe, Interfacing single photons and single quantum dots with photonic nanostructuresRev. Mod. Phys. 87, 347 (2015).
Quantum dots in photonic nanostructures: a platform for all-solid-state quantum optics
hole
electron
Excitons for single-photon emission
Single electron (or hole) as optically adressable
Building Blocks for Integrated Quantum
Photonic Circuits
Single-photon source and nonlinearity
Efficient coupling to dielectric waveguides for long-range propagation
Photon circuits based on dielectric waveguides
On-chip single-photon detectors based on superconducting nanowires
Lodahl, Mahmoodian & Stobbe, Interfacing single photons and single quantum dots with photonic nanostructuresRev. Mod. Phys. 87, 347 (2015).
QUANTOP
QUANTOP
Semiconductor
• Opto-mechanics (membrane)
Atoms
• Nanofibre
• Glass cell
Hybrid (membrane + atoms)
QUANTOP
Quantum Membranes
• Only 100 nm thick• Few mK• Single phonon level• Light Squeezing
QUANTOP
Nanofibre
Quantum State Engineering
Quantum Metrology
Quantum Information
QUANTOP
Caesium vapour cells
• An ensemble of longlived spins
Applications
• Biomagnetometry
• Quantum Information:– Entanglement
– Teleportation
– Single photon source
mF = 4
mF = 3
Zeeman
splitting1b
mF = 2
Positivefrequencyoscillator
Negativefrequencyoscillator
𝑋 𝑡 − 𝑋0 𝑡 = 𝑋 0 −𝑋0 0 ]cos 𝜔𝑡 + [𝑃 0 + 𝑃0 0 sin 𝜔𝑡
Entanglement of an oscillator with an atomic spin
J
Synchronizedto better than
Standard QuantumLimit
4/1)()( PVarXVar * * <
On-demand single photon source
Motivation• Various applications in quantum information
(e.g. cryptography, quantum simulators)• Focus: Quantum repeater
≠
Read
4
3
3'
4'
5'
F
3 4 5mF
9.2 GHz|1>
|0>
~1 GHz
Single Photon
On-demand single photon source
4
3
3'
4'
5'
F
3 4 5mF
Write
9.2 GHz|1>
|0>
~1 GHz
heralding
Single Photon
|𝜓 ∝
𝑗=1
𝑁
𝑐𝑗𝑒𝑖∆𝒌∙𝒓 |𝑔1𝑔2…𝑠𝑗 … 𝑔𝑁
[1]
[1] Heng Shen, PhD Thesis, University of Copenhagen, 2015
Quantum Optics and Atomic Physics