124 research outputs found
Controlling fast transport of cold trapped ions
We realize fast transport of ions in a segmented micro-structured Paul trap.
The ion is shuttled over a distance of more than 10^4 times its groundstate
wavefunction size during only 5 motional cycles of the trap (280 micro meter in
3.6 micro seconds). Starting from a ground-state-cooled ion, we find an
optimized transport such that the energy increase is as low as 0.10 0.01
motional quanta. In addition, we demonstrate that quantum information stored in
a spin-motion entangled state is preserved throughout the transport. Shuttling
operations are concatenated, as a proof-of-principle for the shuttling-based
architecture to scalable ion trap quantum computing.Comment: 5 pages, 4 figure
On the Ground State of Two Flavor Color Superconductor
The diquark condensate susceptibility in neutral color superconductor at
moderate baryon density is calculated in the frame of two flavor
Nambu-Jona-Lasinio model. When color chemical potential is introduced to keep
charge neutrality, the diquark condensate susceptibility is negative in the
directions without diquark condensate in color space, which may be regarded as
a signal of the instability of the conventional ground state with only diquark
condensate in the color 3 direction.Comment: 4 pages, 2 figure
Cryogenic setup for trapped ion quantum computing
We report on the design of a cryogenic setup for trapped ion quantum
computing containing a segmented surface electrode trap. The heat shield of our
cryostat is designed to attenuate alternating magnetic field noise, resulting
in 120~dB reduction of 50~Hz noise along the magnetic field axis. We combine
this efficient magnetic shielding with high optical access required for single
ion addressing as well as for efficient state detection by placing two lenses
each with numerical aperture 0.23 inside the inner heat shield. The cryostat
design incorporates vibration isolation to avoid decoherence of optical qubits
due to the motion of the cryostat. We measure vibrations of the cryostat of
less than 20~nm over 2~s. In addition to the cryogenic apparatus, we
describe the setup required for an operation with
Ca and Sr ions.
The instability of the laser manipulating the optical qubits in
Ca is characterized yielding a minimum of its
Allan deviation of 2.410 at 0.33~s. To evaluate the
performance of the apparatus, we trapped Ca
ions, obtaining a heating rate of 2.14(16)~phonons/s and a Gaussian decay of
the Ramsey contrast with a 1/e-time of 18.2(8)~ms
Lowering the critical temperature with eight-quark interactions
It is shown that eight-quark interactions, which are needed to stabilize the
ground state of the combined three flavor Nambu -- Jona-Lasinio and 't Hooft
Lagrangians, play also an important role in determining the critical
temperature at which transitions occur from the dynamically broken chiral phase
to the symmetric phase.Comment: 4 pages, 2 figure
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