391 research outputs found
Indirect Probe of Electroweak-Interacting Particles with Mono-Lepton Signatures at Hadron Colliders
Electroweak-interacting massive particles (EWIMPs) exist in a broad class of
new physics models beyond the Standard Model. Searching for such particles is
one of most primary goal at the LHC and future colliders. The EWIMP generally
affects the LHC signatures through quantum corrections even without direct
productions. By measuring the Standard Model processes precisely, we can
indirectly probe the EWIMPs. In this paper, we study the current constraint and
future prospect of the EWIMPs by using the precision measurements of
mono-lepton production from the charged Drell-Yan processes at hadron
colliders. We found the mono-lepton signature can be a better probe than
dilepton signature from the neutral Drell-Yan processes.Comment: 10 pages, 7 figure
Serial-parallel conversion for single photons with heralding signals
We present serial-parallel conversion for a heralded single photon source
(heralded SPS). We theoretically show that with the heralding signal, the
serial-parallel converter can route a stream of n photons to n different
spatial modes more efficiently than is the case without using a heralding
signal. We also experimentally demonstrate serial-parallel conversion for two
photons generated from a heralded SPS. We achieve a conversion efficiency of
0.533 \pm 0.003, which exceeds the maximum achievable efficiency of 0.5 for
serial-parallel conversion using unheralded photons, and is double the
efficiency (0.25) for that using beamsplitters. When the losses in the optical
converter are corrected for, the efficiency of the current setup can be
increased up to 0.996 \pm 0.006.Comment: 8 pages, 5 figure
Nonlocal Position Changes of a Photon Revealed by Quantum Routers
Since its publication, Aharonov and Vaidman's three-box paradox has undergone
three major advances: i). A non-counterfactual scheme by the same authors in
2003 with strong rather than weak measurements for verifying the particle's
subtle presence in two boxes. ii) A realization of the latter by Okamoto and
Takeuchi in 2016. iii) A dynamic version by Aharonov et al. in 2017, with
disappearance and reappearance of the particle. We now combine these advances
together. Using photonic quantum routers the particle acts like a quantum
"shutter." It is initially split between Boxes A, B and C, the latter located
far away from the former two. The shutter particle's whereabouts can then be
followed by a probe photon, split in both space and time and reflected by the
shutter in its varying locations. Measuring the former is expected to reveal
the following time-evolution: The shutter particle was, with certainty, in
boxes A+C at t1, then only in C at t2, and finally in B+C at t3. Another branch
of the split probe photon can show that boxes A+B were empty at t2. A Bell-like
theorem applied to this experiment challenges any alternative interpretation
that avoids disappearance-reappearance in favor of local hidden variables.Comment: Revised versio
Demonstration of an optical quantum controlled-NOT gate without path interference
We report the first experimental demonstration of an optical quantum
controlled-NOT gate without any path interference, where the two interacting
path interferometers of the original proposals (Phys. Rev. A {\bf 66}, 024308
(2001), Phys. Rev. A {\bf 65}, 012314 (2002)) have been replaced by three
partially polarizing beam splitters with suitable polarization dependent
transmittances and reflectances. The performance of the device is evaluated
using a recently proposed method (Phys. Rev. Lett. {\bf 94}, 160504 (2005)), by
which the quantum process fidelity and the entanglement capability can be
estimated from the 32 measurement results of two classical truth tables,
significantly less than the 256 measurement results required for full quantum
tomography.Comment: 4 pages, 3 figure
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