Microwave coherent spectroscopy of ultracold thulium atoms
D. A. Pershin, V. V. Yaroshenko, V. V. Tsyganok, V. A. Khlebnikov, E. T. Davletov, D. V. Shaykin, E. R. Gadylshin, I. S. Cojocaru, E. L. Svechnikov, P. V. Kapitanova, A. V. Akimov
Recently, the thulium atom was cooled down to the Bose-Einstein condensation temperature, thus opening a pathway to quantum simulation with this atom. However, successful simulations require instruments to control and readout states of the atom as well as the ability to control the interaction between either different species or different states of the same type of species. In this paper, we provide an experimental demonstration of high-fidelity (over 93%) manipulation of the ground state magnetic sublevels of thulium, which utilizes a simple and efficient design of a microwave (MW) antenna. The coherence time and dephasing rate of the energetically highest hyperfine level of the ground state were also examined.
Recent studies demonstrated anomalous temperature shifts for some Fano-Feshbach resonances of thulium atoms. These anomalies were explained by the variation in light intensity in the optical dipole trap, which accompanied changes in temperature. In addition, a temperature-related transformation of the statistics of the interresonance spacing was demonstrated [1]. Here, we analyze the shifts of isolated s- and d-type Fano-Feshbach resonances of ultracold thulium atoms with temperature for a fixed depth of an optical dipole trap. The measurements are consistent with the 3-body recombination-base…
Factor of 1000 suppression of the depolarization rate in ultracold thulium collisions
Russian Quantum Center（俄罗斯量子中心）；Moscow Institute of Physics and Technology（莫斯科物理技术学院）；PN Lebedev Institute RAS（列别捷夫物理研究所）；Bauman Moscow State Technical University（鲍曼国立技术大学）
We report on building of a compact vacuum chamber for spectroscopy of ultracold thulium and trapping of up to 13 million atoms. Compactness is achieved by obviating a classical Zeeman slower section and placing an atomic oven close to a magneto-optical trap (MOT), specifically at the distance of 11 cm. In this configuration, we significantly gained in solid angle of an atomic beam, which is affected by MOT laser beams, and reached 1 million atoms loaded directly in the MOT. By exploiting Zeeman-like deceleration of atoms with an additional laser beam, we increased the number of trapped atoms t…
We have demonstrated microwave-assisted coherent control of ultracold $^{85}$Rb$^{133}$Cs molecules with a ladder-type configuration of rotational states. A probe microwave (MW) field is used to couple a lower state $X^1Σ^+(v=0, J=1)$ and a middle state $X^1Σ^+(v=0, J=2)$, while a control MW field couples the middle state and a upper state $X^1Σ^+(v=0, J=3)$. In the presence of the control field, the population of middle rotational states, $X^1Σ^+(v=0, J=2)$, can be reduced by a control MW field. Broadening of spectral splitting and shift of central frequency in this coherent spectrum are obse…
We report the observation of microwave coherent control of rotational states of ultracold $^{85}$Rb$^{133}$Cs molecules formed in their vibronic ground state by short-range photoassociation. Molecules are formed in the single rotational state $X(v=0,J=1)$ by exciting pairs of atoms to the short-range state $(2)^{3}Π_{0^{-}} (v=11, J=0)$, followed by spontaneous decay. We use depletion spectroscopy to record the dynamic evolution of the population distribution and observe clear Rabi oscillations while irradiating on a microwave transition between coupled neighbouring rotational levels. A densit…
Harnessing the potential wide-ranging quantum science applications of molecules will require control of their interactions. Here, we use microwave radiation to directly engineer and tune the interaction potentials between ultracold calcium monofluoride (CaF) molecules. By merging two optical tweezers, each containing a single molecule, we probe collisions in three dimensions. The correct combination of microwave frequency and power creates an effective repulsive shield, which suppresses the inelastic loss rate by a factor of six, in agreement with theoretical calculations. The demonstrated mic…
我们用微波来设计超冷极性分子之间的排斥性长程相互作用。所得到的屏蔽抑制了各种损耗机制并提供了大的弹性截面。超精细相互作用限制了实际条件下的屏蔽，但磁场允许将损耗抑制到10-14 cm 3 s-1以下。屏蔽的机制和最佳条件与Gorshkov等人[Phys. Rev. Lett. 101，073201（2008）]，并且不需要消除对于许多应用至关重要的长程偶极-偶极相互作用。
We theoretically study collisions between ultracold polar molecules that are polarized by microwave or static electric fields. We systematically study the dependence on field strength, microwave polarization, and detuning from rotational transitions. We calculate the loss in two-body collisions that is observable experimentally and compare to the results expected for purely first-order dipolar interactions. For ground state molecules polarized by a static electric field, the dynamics are accurately described by first-order dipolar interactions. For microwave dressing, instead, resonant dipolar…
We explore coherent multi-photon processes in $^{87}$Rb$^{133}$Cs molecules using 3-level lambda and ladder configurations of rotational and hyperfine states, and discuss their relevance to future applications in quantum computation and quantum simulation. In the lambda configuration, we demonstrate the driving of population between two hyperfine levels of the rotational ground state via a two-photon Raman transition. Such pairs of states may be used in the future as a quantum memory, and we measure a Ramsey coherence time for a superposition of these states of 58(9) ms. In the ladder configur…
Resonant dipolar collisions of ultracold molecules induced by microwave dressing
我们演示了微波敷料上的超冷，费米子${}^{23}$ Na ${}^{40}$ K基态分子和观察共振偶极碰撞的横截面超过三倍的$s$波幺正极限。这些碰撞的起源是接近分子的偶极子沿着分子间轴的共振排列，这导致了强烈的吸引力。我们解释我们的观察与一个概念上简单的两个国家的图片的基础上的康登近似。此外，我们进行耦合通道的计算，同意与实验观察到的碰撞率。虽然这里观察到的碰撞作为激光诱导的损失，微波敷料上的化学稳定的分子被困在盒电位可以使分子的强烈相互作用的偶极气体的创建。
Generation of strong ultralow-phase-noise microwave fields with tunable ellipticity for ultracold polar molecules
Max-Planck-Institut für Quantenoptik（马克斯·普朗克量子光学研究所）；Munich Center for Quantum Science and Technology（慕尼黑量子科学与技术中心）；Technische Universität München（慕尼黑工业大学）；Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien（维也纳量子科学与技术中心，原子研究所，维也纳工业大学）；Fakultät für Physik, Ludwig-Maximilians-Universität（路德维希-马克西米利安大学物理学院）
We report measurements of the ac polarizabilities of ultracold ground-state $^{23}\rm{Na}^{87}\rm{Rb}$ molecules. While the polarizability of the ground rotational state $J = 0$ is isotropic, that of the first excited rotational state $J = 1$ is anisotropic and depends strongly on the light polarization angle. We obtain both polarizabilities precisely by combining trap oscillation frequency measurement and high resolution rotational spectroscopy driven by microwave. With the optimized light polarization angle and intensity combination, the nonuniformity of the differential ac Stark shift betwe…
High-resolution Internal State Control of Ultracold $^{23}$Na$^{87}$Rb Molecules
我们报道了对超冷$^{23}$ Na $^{87}$ Rb分子内部状态的完全控制，包括振动、转动和超精细自由度。从一个弱束缚Feshbach分子的样品出发，利用高效率、高分辨率的受激拉曼绝热通道，实现了分子在振转基态和激发态的单超精细能级的产生.从振转和超精细基态，我们演示了旋转和超精细控制与单光子和双光子微波光谱。这一完全控制分子内部状态的成就为研究态依赖的分子碰撞和态控制的化学反应铺平了道路。
An ensemble of excited atoms can synchronize emission of light collectively in a process known as superradiance when its characteristic size is smaller than the wavelength of emitted photons. The underlying superradiance depends strongly on electromagnetic (photon) fields surrounding the atomic ensemble. High mode densities of microwave photons from $300\,$K blackbody radiation (BBR) significantly enhance decay rates of Rydberg states to neighbouring states, enabling superradiance that is not possible with bare vacuum induced spontaneous decay. Here we report observations of the superradiance …
Ultracold polar molecules offer strong electric dipole moments and rich internal structure, which makes them ideal building blocks to explore exotic quantum matter, implement novel quantum information schemes, or test fundamental symmetries of nature. Realizing their full potential requires cooling interacting molecular gases deeply into the quantum degenerate regime. However, the complexity of molecules which makes their collisions intrinsically unstable at the short range, even for nonreactive molecules, has so far prevented the cooling to quantum degeneracy in three dimensions. Here, we dem…
Quantum many-body phases offer unique properties and emergent phenomena, making them an active area of research. A promising approach for their experimental realization in model systems is to adiabatically follow the ground state of a quantum Hamiltonian from a product state of isolated particles to one that is strongly-correlated. Such protocols are relevant also more broadly in coherent quantum annealing and adiabatic quantum computing. Here we explore one such protocol in a system of ultracold atoms in an optical lattice. A fully magnetized state is connected to a correlated zero-magnetizat…
Low-entropy arrays of microwave-shielded molecules prepared by interaction blockade
Institute for Molecules and Materials, Radboud University（鲁道夫大学分子与材料研究所）；Department of Physics, Columbia University（哥伦比亚大学物理系）；James Franck Institute and Department of Physics, The University of Chicago（芝加哥大学詹姆斯·弗兰克研究所和物理系）
Hybrid quantum systems involving cold atoms and microwave resonators can enable cavity-mediated infinite-range interactions between atomic spin systems and realize atomic quantum memories and transducers for microwave to optical conversion. To achieve strong coupling of atoms to on-chip microwave resonators, it was suggested to use atomic Rydberg states with strong electric dipole transitions. Here we report on the realization of coherent coupling of a Rydberg transition of ultracold atoms trapped on an integrated superconducting atom chip to the microwave field of an on-chip coplanar waveguid…
Identical-Particle Symmetry-Enabled Complete Coherent Control of Ultracold Atomic and Molecular Collisions
University of Maryland（马里兰大学）；National Institute of Standards and Technology (NIST)（美国国家标准与技术研究院）；University of Toronto（多伦多大学）；University of Nevada, Reno（内华达大学里诺分校）
