We report observations of entanglement two remote atomic qubits, achieved by generating an entangled state qubit and a single photon at site $A$, transmitting the to $B$ in adjacent laboratory through optical fiber, converting into qubit. Entanglement qubits is inferred performing, locally, quantum transfer each onto photonic subsequent measurement polarization correlations violation Bell inequality $|S|\ensuremath{\le}2$. experimentally determine...

We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After programmable delay, the excitation is converted into photon (idler). Polarization both signal and idler recorded found be in violation Bell inequality. Atomic coherence times exceeding several microseconds achieved by switching off all trapping fields - including quadrupole magnetic field...

In a light-pulse atom interferometer, we use tip-tilt mirror to remove the influence of Coriolis force from Earth's rotation and characterize configuration space wave packets. For interferometers with large momentum transfer pulse separation time, improve contrast by up 350% suppress systematic effects. We also reach what is our knowledge largest space-time area enclosed in any interferometer date. discuss implications for future high-performance instruments.

Historically, time measurements have been based on oscillation frequencies in systems of particles, from the motion celestial bodies to atomic transitions. Relativity and quantum mechanics show that even a single particle mass m determines Compton frequency ω(0) = mc(2)/[formula: see text] where c is speed light [formula: Planck's constant h divided by 2π. A clock referenced would enable high-precision fundamental definition second. We demonstrate such using an optical comb self-reference...

A source of deterministic single photons is proposed and demonstrated by the application a measurement-based feedback protocol to heralded single-photon consisting an ensemble cold rubidium atoms. Our stationary produces photoelectric detection record with sub-Poissonian statistics.

Abstract As one of the most influential experiments on development modern macroscopic theory from Newtonian mechanics to Einstein’s special relativity, phenomenon light dragging in a moving medium has been discussed and observed extensively different types systems. To have significant effect, long duration travelling is preferred. Here we demonstrate light-dragging experiment an electromagnetically induced transparent cold atomic ensemble enhance effect by at least three orders magnitude...

A quantum repeater is a system for long-distance communication that employs memory elements to mitigate optical fiber transmission losses. The multiplexed (O. A. Collins, S. D. Jenkins, Kuzmich, and T. B. Kennedy, Phys. Rev. Lett. 98, 060502 (2007)) has been shown theoretically reduce time requirements. We present an initial implementation of element in cold rubidium gas. show it possible create atomic excitations arbitrary pairs demonstrate the violation Bell's inequality light fields...

We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. null increase sensitivity interferometer by combining with Bloch oscillations. demonstrate agreement between experiment theory, a 1500-fold reduction phase, limited measurement noise. In addition to reduced systematic effects, our has high contrast up 4.4×10(6) radians difference, resolution fine structure constant δα/α=0.25 ppb 25 h...

We present a study of Doppler-sensitive light-pulse atom interferometers operating within optical dipole potentials, where atomic trajectories are manipulated using momentum transfer from light pulses and forces the trap. Efficient methods introduced to minimize inhomogeneous broadening oscillation frequencies in atoms confined three-dimensional lattice These techniques enable preparation various quantum states, including vacuum, thermal, squeezed for interferometry. Additionally, we...

Matter-wave interference is demonstrated with light in a micrometer-size hollow-core photonic crystal fiber.

We observe quantum, Hong-Ou-Mandel, interference of fields produced by two remote atomic memories. High-visibility is obtained utilizing the finite memory time in four-photon delayed coincidence measurements. Interference from memories a crucial element protocols for scalable generation multi-node qubit entanglement.

By time-dependent variation of a control field, both coherent and single-photon states light are stored in, retrieved from, cold atomic gas. The efficiency retrieval is studied as function the storage time in an applied magnetic field. A series collapses revivals observed, very good agreement with theoretical predictions. observations interpreted terms evolution collective excitation spin wave wave, known dark-state polariton.

Quantum sensing and quantum information processing use advantages such as squeezed states that encode a quantity of interest with higher precision generate correlations to outperform classical methods. In harmonic oscillators, the rate generating squeezing is set by speed limit. Therefore, degree which advantage can be used in practice limited time needed create state relative unavoidable decoherence. Alternatively, sudden change oscillator's frequency projects ground into circumvent...

Quantum engineering using photonic structures offer new capabilities for atom-photon interactions quantum optics and atomic physics, which could eventually lead to integrated devices. Despite the rapid progress in variety of structures, coherent excitation motional states atoms a waveguide guided modes has yet be demonstrated. Here, we use mode hollow-core crystal fibre manipulate mechanical Fock single harmonic potential inside fibre. We create large array Schr\"odinger cat states,...

Confining particles in hollow-core photonic crystal fibers has opened up new prospects to scale the distance and time over which can be made interact with light. However, maintaining long-lived quantum spin coherence and/or transporting it macroscopic distances a waveguide remain challenging. Here, we demonstrate coherent guiding of ground-state superpositions 85Rb atoms centimeter range hundreds milliseconds inside fiber. The decoherence is mainly due dephasing from residual differential...

We propose and demonstrate an atomic qubit based on a cold $^{85}$Rb-$^{87}$Rb isotopic mixture, entangled with frequency-encoded optical qubit. The interface of single spatial light mode, the ability to independently address two states, should provide basic element interferometrically robust quantum network.

We study the use of atom interferometers as detectors for gravitational waves in mHz - Hz frequency band, which is complementary to planned optical interferometers, such laser interferometer wave observatories (LIGOs) and Laser Interferometer Space Antenna (LISA). describe an optimized atomic interferometric sensor (AGIS), whose sensitivity proportional baseline length power 5/2, opposed linear scaling a more conservative design. Technical challenges are briefly discussed, table-top...

Quantum mechanics provides a mechanism for absolutely secure communication between remote parties. For distances greater than 100 km, direct quantum via optical fiber is not viable, owing to losses, and intermediate storage of the information along transmission channel necessary. This leads concept repeater, proposed by Briegel et al. [Phys. Rev. Lett. 81, 169 (1998)]. Duan [Nature 414, 413 (2001)] have use atomic ensembles as basic memory elements repeater. We provide an overview our...

Traditionally, measuring the center-of-mass (c.m.) velocity of an atomic ensemble relies on Doppler shift absorption spectrum single atoms in ensemble. Mapping out distribution is indispensable when determining c.m. using this technique. As a result, highly sensitive measurements require preparation with narrow width. Here, we use dispersive measurement light passing through moving room temperature vapor cell to determine shot short-term sensitivity $5.5\text{ }\text{...

The authors demonstrate storage of light in an optical fiber over 50 ms. result is equivalent to 8.7X10${}^{\ensuremath{-}5}$ dB/$\ensuremath{\mu}$s or 2.9X10${}^{\ensuremath{-}4}$ dB/km propagation loss the fiber.

We demonstrate an inertia sensitive atom interferometer optically guided inside a 22-cm-long negative curvature hollow-core photonic crystal fiber with time of 20 ms. The result improves the previous sensitivity by three orders magnitude. improvement arises from realization in-fiber Λ-enhanced gray molasses and delta-kick cooling to cool atoms 32μK below 1μK in 4 overcomes inevitable heating during loading process allows shallow guiding optical potential minimize decoherence. Our results...

We demonstrate the laser cooling of $^{85}\mathrm{Rb}$ atoms in a two-dimensional optical lattice. follow two-step degenerate Raman sideband scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where fast to an auxiliary state is followed by slow dark state. This method has advantage independent control heating rate and from pumping beam. operate lattice at Lamb-Dicke parameter $\ensuremath{\eta}=0.45$ show spin-polarized recoil temperature both dimensions within 2.4 ms with aid...

Two-mode squeezed states, which are entangled states with bipartite quantum correlations in continuous-variable systems, crucial information processing and metrology. Recently, computing the vibrational modes of trapped atoms has emerged significant progress, featuring a high degree control hybridizing spin qubits. Creating two-mode such platform could enable applications that only viable photons. Here, we experimentally demonstrate by employing two-dimensional optical lattice as registers....