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Experimental Atomic Physics
Principal Investigator: Vladan Vuletić
Graduate Students:
Kristin Beck, Boris Braverman,
Alexei Bylinskii, Wenlan Chen,
Dorian Gangloff, Jiazhong Hu,
Akio Kawasaki, Qiyu Liang, Özge Özel,
Thibault Peyronel, Hao Zhang
Postdoctoral Associates/Fellows:
Ofer Firstenberg, Leon Karpa,
Robert McConnell
Atomic
Physics
The Vuletić group strives to manipulate atoms and photons in systems where the particles’ quantum nature dominates.
Our work touches on quantum measurement, quantum control, quantum feedback, mesoscopic systems and entanglement.
Current projects include:
Nonlinearities at the single photon level
exploiting electromagnetically induced transparency (EIT) to control the quantum statistics of light
100s
1/2
1
g(2)()
1 photon/s
2 photons/s
4 photons/s
6 photons/s
0.8
46s
1/2
0.6
1
0.4
0
0.2
10
20
[2 MHz]
30
0
0
0.5
0
0.5
 [s]
1
1
 [s]
1.5
autocorrelation function of output light
By combining EIT and atomic
excitation into Rydberg states,
in which the outer electron is in
a highly excited state (n~100),
we observe efficient, long-range
interactions between single photons.
One application of this nonlinearity is
photon blockade, which suppresses
photon pairs travelling together.
Switching with Single Photons
We have also observed nonlinearities
between two different spatial modes of
light. Using a high finesse cavity and an EIT
medium, we created a switch. The system is
transparent for single photons, which either
travel through a resonant cavity or the EIT
window. However, when a photon occupies
each of the modes, transmission is reduced
switching the photons off.
g2(τ)
Spatially Separating Photons
τ (nS)
cross correlation function of output light
Measurements beyond the standard quantum limit
using ensembles of atoms in high finesse optical cavities to beat the standard quantum limit
Better Atomic Clocks
Counting Many Atoms
State-of-the-art atomic clocks have
-16
relative uncertainties of 10 . Quantum
mechanics predicts we can do better.
We are building an atomic clock that
will use spin squeezing in 171Yb atoms
to measure the frequency of an
optical transition—and the corresponding
decay time 1/f—with uncertainties lower
than the standard quantum limit.
measured variance of atom number below the SQL
Beating the standard quantum limit
requires high-fidelity state detection
for large ensembles of atoms. Using a
cavity-based detection scheme, we
resolve up to 100 antinode-equivalent
atoms with single atom resolution.
Using this scheme, we achieve
measurement variances 21dB below the
projection noise limit.
Cooling and trapping techniques
Stabilizing Ions with Light
Ions are a promising qubit for quantum computation. Ions are standardly trapped
with time varying (RF) electric fields. These traps are limited in size and by
micromotion, residual motion inherent in these RF traps. We are developing a new
technique that uses an optical standing wave to stabilize and cool a linear array
of ions. Our method also allows much finer spatial resolution than RF traps.
For recent publications, visit our website: www.rle.mit.edu/eap/
We gratefully acknowledge funding from the NSF, the ONR, and DARPA. Individuals are partly
supported by the Department of Physics, the NSF, the Alexander von Humboldt-Foundation and NSERC.