Fast and accurate Raman spinor matterwave control is key to implementing advanced quantum technology for quantum sensing, simulation, and computation. Typical Raman controls are achieved at large single-photon detunings, not only to avoid spontaneous emissions but also for reducing the differential Stark shifts. Our work focuses on moderate single-photon detuning where the universal rotations...
The mass tests of equivalence principle (EP) with atoms have been performed using ^[85]Rb-^[87]Rb, ^[87]Rb-^[39]K, and ^[88}Sr-^[87}Sr atom pairs [1–7]. Beyond-mass tests have been investigated using different quantum properties, including quantum statistics [8], spin [9,10], superposition [11], and internal energy [1,10,11]. An entanglement test [12] was also proposed. All of these quantum...
$~~~~$Quantum correlations are the central features characterizing many-body physics, which become one of the most important observables in many experiments. Here we present an alternate scheme both theoretically and experimentally, probing the equilibrium correlations by ramping dynamics which can tell a strong correlated system has well-defined quasi-particle descriptions or not. By ramping...
A segmented-blade ion trap with biasing rods
Jungsoo Hong,1 Myunghun Kim,1 Keumhyun Kim,1 Wonchan lee,2 Hyegoo Lee,1 Youngill Moon,1 Moonjoo lee1
1Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), 37673 Pohang,...
The frequency-correlated biphotons are an excellent resource for long-distance quantum communication. They can be generated from the diamond-type atomic level structures under four-wave mixing in an alkali metal atomic ensemble. The signal photon from the upper transition has low-loss telecom bandwidth useful in a fiber-based quantum network, while the idler photon from the lower transition...
The Cold Atom Physics Rack (CAPR) of Chinese space station will be launched at the end of 2022. The important goal of CAPR is to achieve BEC at 100pk. In order to obtain ultracold atoms in microgravity of space station, we propose a two-stage cooling scheme using all-optical trap with different waist beams. The cold atom cloud obtained by this scheme is composed of condensate and thermal atoms...
Since the first demonstration of laser cooling and trapping, cold and ultracold trapped atoms have played a vital role in realizing many modern advanced atomic physic experiments through a coherent control of matter-light interaction. Among various trapped cold atomic species, Strontium atoms has become one of the interesting candidates in realizing various experimental platforms from quantum...
Acousto-optical modulators are ubiquitously equipped in modern research labs across fields for modulation of amplitude, phase, frequency and propagation direction of light. Efficient AOM diffraction relies on phase-matching the light beams with the sound wave. Deviation of operation parameters from the pre-aligned Bragg condition leads to reduced diffraction efficiency and distorted...
Accurate control of single emitters at nanophotonic interfaces may greatly expand the accessible quantum states of coupled optical spins in the confined geometry and to unveil exotic nonlinear quantum optical effects. However, the optical control is challenged by spatially varying light-atom coupling strength generic to nanophotonics. We demonstrate numerically that despite the near-field...
Interactions of positron and positronium (Ps) with atoms and ions have been extensively studied in recent years, with great attention being paid to the formation of weakly bound states of positronic complexes [1,2], the collision and electron-positron annihilation processes [3]. However, accurate $\textit{ab initio}$ description of these systems is challenging due to the complicated...
Interaction of light with a dense cloud of ultracold atoms is an open-system many-body problem. Even within the linear optics regime, interesting effects beyond effective medium theory can arise from near-field interaction and multiple scatterings. On the other hand, when subjecting to strong optical excitions, the coupled quantum dynamics involves long-range dipole correlations defined in an...
Optically trapped mixed-species single atom array with arbitrary geometry is an attractive and promising platform for various applications, because tunable quantum system with multiple components provides extra degrees of freedom for experimental control. Here, we report the first demonstration of two-dimensional $6\times4$ dual-species atom assembly with a filling fraction of 0.88 (0.89) for...
Significant aspects of advanced quantum technology today rely on rapid Raman control of atomic hyperfine matterwaves. Unfortunately, efficient Raman excitations are usually accompanied by uncompensated dynamic phases and coherent spin-leakages, preventing accurate and repetitive transfer of recoil momentum to large samples. We provide systematic study to demonstrate that the limitations can be...
We demonstrate how dimensions of many-body systems influence the critical dynamical behaviors at quantum phase transition. We perform our experiment in a quasi-two-dimensional Bose-Hubbard model and do the improved band-mapping method to measure the quasi-momentum distribution. Based on these measurements, we obtain the components of coherent and incoherent parts in the mixture of superfluid...
A ground state atom immersed in the wave function of the valence electron of a Rydberg atom can generate a long-range Rydberg molecule (LRRM). In this work, using the multipole expansion of the electrostatic interaction in prolate spheroidal coordinates, approximate and compact expressions of the electrostatic potential that determine the chemistry of trilobite and butterfly LRRM are explored....
Title: Enhanced antiferromagnetism driven by superexchange interaction in a three-component Fermi-Hubbard model
Author：Ren Liao1, Jingxin Sun1, Pengju Zhao2, Shifeng Yang1, Hui Li1, Xinyi Huang1, Wei Xiong1, Xiaoji Zhou1, Dingping Li2, Xiongjun Liu2 and Xuzong Chen1
1. School of Electronics, Peking University, Beijing 100871, China;
2. School of Physics, Peking University, Beijing 100871,...
Resolved sideband cooling provides an important technique in preparing the trapped ions to their motional ground state, which is essential in ion-based quantum computation. Here we present a surpassing sideband cooling performance in trapped ions utilizing light-mediated dipole-dipole interactions among them. By placing the ions at magic interparticle distances, we find that the target ion can...
Synopsis The asymmetric profiles of Fano interference in the thin-film planar cavity have been studied by changing the nuclear abundance. It is found that the resonant nuclear resonance seems to be unexcited superficially at a critical nuclear abundance in the overcritical regime and the reflectivity shows a flat line. The mechanism behind the flat line is the controllable relative...
The ultracold atoms are an excellent platform to simulate complex quantum many-body systems of condensed-matter physics. We discuss the quantum phases of a two-dimensional spin-orbit coupled bosons in an optical lattice. This system breaks the rotational symmetry in momentum-space and the condensation occurs at finite momentum. The interplay of single-particle hopping, strength of spin-orbit...
Precise imaging is instrumental to ultracold atomic technology both for precision measurements and for quantum simulation of many-body physics. Comparing with regular imaging techniques, holographic imaging based on phase-retrieval extends the measurement observables from real to complex numbers and therefore supports single-shot spectroscopic measurements even in presence of atomic column...
We develop a two-dimensional bottle beam array for laser trapping atoms in the ground and Rydberg states. A dipole-trap laser beam is diffracted by a phase spatial light modulator imprinted with a phase pattern to generate a 6 by 6 array of the bottled beam. The beam arrays are then focused by an aspheric lens and imaged by a CCD camera. The distance between two nearest-neighbour atoms is 396...
From laser cooling to light-pulse atom interferometry, precise control of light-atom interaction requires precise modulation of optical waveforms in the time-domain. To this end, Acousto-Optical Modulation (AOM) is uniquely powerful for achieving high speed, high contrast optical control. However, based on two-mode resonant Bragg diffraction, the AOM efficiency and bandwidth are prone to...
Nonequilibrium physics and many-body dynamic behavior is an important and challenging question in modern physics. We using the cold atomic inhomogeneous optical lattice system investigate dynamic quantum phase transition from superfluid to Mott insulator. We use a new method to measure the quasi-momentum distribution and define the observable physical quantities based on it. According...
Using the confined variational method, the low-energy $S$-wave elastic scattering of positronium from molecular hydrogen is studied nonadiabatically at incident energy up to $0.13$~eV [1]. Accurate $S$-wave phase shifts, scattering lengths, and cross sections are calculated and compared with other theoretical and experimental values. Using the modified effective range formula, the $S$-wave...
In the quantum network, a biphoton source can be utilized to transmit Hadamard codes with high coincidence rates. It is the strong correlation in the biphoton state that facilitates the encoding and decoding task. We propose to multiplex the biphoton state from the cascade emissions of cold atomic ensembles under the four-wave mixing condition, and use this effective biphoton state to fulfill...
The Hall effect, originating from the motion of charged particles in magnetic fields, has deep consequences for the description of materials, extending far beyond condensed matter. Understanding such an effect in interacting systems represents a fundamental challenge, even for small magnetic fields. In a very recent work, we use an atomic quantum simulator to track the motion of ultracold...
Cold atoms are useful for many quantum information applications. Their strong interactions with light give them many uses in atom-photon junctions. However, one difficulty with cold atoms is integrating them with waveguides and other photonic devices. Here we demonstrate a method that involves trapping the atoms inside a laser drilled hole through an optical fibre. By carefully selecting the...
High precision measurements of the electron spin and orbital g-factors complement very well, the atomic/molecular experiments which test for parity, search for a permanent electric dipole moment, and investigate QED. In this talk, experimental evidence will be presented to show that the electron orbital g-factor is significantly anomalous. A search for an anomaly in the electron g-factors,...
Abstract: The atom-interferometer gyroscope has been proven to be a promising tool for high-precision rotation measurements, and it will have important applications in fields of fundamental physics, geophysics, and inertia navigation. Here, we present the recent progress of our atom-interferometer gyroscope. First, with a compact atom-interferometer gyroscope, we demonstrated the rotation...
Here the recent progress on the $\rm{Ca}^{+}$ ion optical clocks will be reported: including a cryogenic $\rm{Ca}^{+}$ ion clock at the liquid nitrogen environment with evaluated uncertainty of 3E-18, and a transportable $\rm{Ca}^{+}$ ion clock with uncertainty of 1.3E-17 and an uptime of ~85% in a month. the clock stability is greatly improved, with long term stability reaching the E-18...
We theoretically study magnetic and orbital correlations in ultracold Fermi gases of alkaline-earth(-like) atoms in one-dimensional state-dependent optical lattices. In particular, with the calculated parameters in the two-orbital Hubbard model realized with ${}^{87}$Sr, ${}^{171}$Yb, and ${}^{173}$Yb atoms, we employ exact diagonalization and matrix product state approaches. We calculate...
Quantum non-demolition (QND) measurement enhances the detection efficiency and measurement fidelity, and is highly desired for its applications in precision measurements and quantum information processing. We propose and demonstrate a QND scheme for the spin state of laser-trapped atoms, allowing the atoms in each spin state to be probed repeatedly. On $^{171}$Yb atoms held in an optical...
We present our recent studs contributed to quantum thermalization in an isolated system utilizing spinor condensates[1][2]. Under the single-mode approximation (SMA), the motional degrees of freedom of spinor condensates are frozen, and all Zeeman components share the same spatial wavefunction. Under such circumstances, the spin dynamics dominates the system's evolution, and the restricted...
Non-Hermiticity is ubiquitous in systems that exchange energy with the environment, and these non-Hermitian systems are sensitive to boundary conditions. Recent years there have seen various studies on non-Hermitian skin effect, where extensive bulk eigenstates pile at open boundaries. Yet, little is known about the role of long-range coupling in a non-Hermitian system. Here we study the...
Title: Simulating an exact one-dimensional transverse Ising model in an optical lattice
Author：Ren Liao1, Fangyu Xiong2 and Xuzong Chen1
1. School of Electronics, Peking University, Beijing 100871, China;
2. School of Physics, Peking University, Beijing 100871, China;
Abstract: A spinless Bose-Hubbard model in a one-dimensional (1D) double-chain tilted lattice is numerically studied at...
We investigate the atomic motion while single, laser-cooled $^{87}$Rb atoms propagate through a high-finesse cavity. Generating a cold trapped atomic ensemble 4-mm above the cavity [[J. Kim$^{\ast}$, K. Kim$^{\ast}$ et al., Sensors 21, 6255 (2021)]][1], the trap is released, and single atoms fall through the resonator mode by gravity. Strong atom-cavity interaction causes large decreases in...
A nanophotonic cavity system strongly coupled to one or multiple neutral atoms is a very useful platform for the quantum information processing. Single qubit control and entanglement between two qubits on this system has been experimentally realized recently based on the fact that the number of atoms coupled to this system has distinct reflectivity spectrum. Here we theoretically studied the...
R. Pratt et al. have called attention to the unsettled observational status for the radiation (intraatomic bremsstrahlung, IAB) expected upon the photoejection of inner shell electrons. We tested for such radiation in the 3 to 7 keV band produced by photoelectrons from the K shell of a copper target upon absorption of an incident 46 keV photon. Exploiting a prediction for the major background...
Fano formula, describing the ubiquitous interference between non-resonance continuum and resonant discrete state, is one of the most important formulas in modern physics [1,2]. As we all known, according to the real number of the line profile index q, the Fano profile can be divided into the symmetric and asymmetric line shape. In this work, we propose a new perspective on the regulation of...
Ultracold atoms in optical lattices are a powerful tool for quantum simulation, precise measurement, and quantum computation. A fundamental problem in applying this quantum system is how to manipulate the higher bands or orbitals in Bloch states effectively. Here we mainly introduce our methods for manipulating high orbital ultracold atoms in optical lattices with different configurations....
Heavy diatomic molecules are currently considered to be among the most sensitive systems used in the search for the P,T-violating effects and in probing of the Standard Model of particle physics. In certain molecules effects resulting from both parity violation and time-reversal violation (P,T - odd effects) are considerably enhanced with respect to atomic systems. The strength of these...
We theoretically examine equilibrium properties of the harmonically trapped ideal Bose and Fermi gases in the quantum degeneracy regime. We analyze thermodynamic characteristics of gases with a finite number of atoms by means of the known semiclassical approach and perform comparison with exact numerical results. For a Fermi gas, we demonstrate deviations in the Fermi energy values originating...
Compared with ultracold atoms, ultracold molecules possess richer internal structure that lend themselves useful for a variety of applications, such as ultracold chemistry, precision measurements, quantum simulation, and quantum computation and so on. A key ingredient in many of above proposed applications is the realization of such a single molecule array, where not only the quantum internal...
CH$_{3}$I is an important trace species in the Earth’s atmosphere, which is mainly produced by biogenic processes. Meanwhile, CH$_{3}$I can release iodine atom, whose ozone depleting efficiency is about two to three orders of magnitude larger than that of chlorine. However, CH$_{3}$I is considered to be relatively environmentally friendly because of its short lifetime in the troposphere due to...
We investigate novel mechanisms of vortex nucleations in a spinor Bose condensate owing to synthetic azimuthal gauge potentials, which are light-induced effective rotations, both theoretically and experimentally. We identify the main mechanism of vortex nucleations as the dynamical instability of low-energy excitations associated with vortex splitting and pair creation at the center of...
