I. G. Koprinkov
Nonadiabatic dressed states of a quantum system interacting with an external electromagnetic field and the environment are presented. The relevant matrix elements within the specified states are found. A closed form expression of the quantum transitions based on the nonadiabatic dressed states is proposed for the first time.
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Non-adiabatic Semiclassical Dressed States
我们引入了一个与振幅和相位都可变的电磁场相互作用的量子系统的非绝热半经典缀饰态，并且存在转储。我们还介绍了一个广义绝热条件，它允许发现封闭形式的解决方案的修饰状态。发现了非绝热因子对振幅场、相位场变化和转储效应引起的修饰态的影响。
Recently, a new method, which can significantly speed up adiabatic quantum state transfer by using dressed states, was proposed by Baksic \emph{et~al.} [Phys. Rev. Lett. \textbf{116}, 230503 (2016)]. Assisted by quantum Zeno dynamics, we develop this dressed-state method to achieve shortcuts to complete and fractional stimulated Raman adiabatic passage for speeding up adiabatic two-atom quantum state transfer and maximum entanglement generation, respectively. By means of some numerical simulations, we determine the parameters used in the scheme which can guarantee the feasibility and efficienc…
Adiabatic creation of entangled states by a bichromatic field designed from the topology of the dressed eigenenergies
研究了双色外场驱动下耦合二态系统纠缠对的制备。我们使用一个两个耦合自旋为1/2的系统，它可以转化为一个三态梯形模型，其中间态代表纠缠态。我们发现，这种纠缠态可以在一个强大的方式与适当的领域。它们的频率和包络线是由模型的拓扑性质导出的。
We report theoretical studies of adiabatic population transfer using dressed spin states. Quantum optimal control using the algorithm of Chopped Random Basis (CRAB) has been implemented in a negatively charged diamond nitrogen vacancy center that is coupled to a strong and resonant microwave field. We show that the dressed spin states are highly effective in suppressing effects of spin dephasing on adiabatic population transfer. The numerical simulation also demonstrates that CRAB-based quantum optimal control can enable an efficient and robust adiabatic population transfer.
We develop new pulse schemes to significantly speed up adiabatic state transfer protocols. Our general strategy involves adding corrections to an initial control Hamiltonian which harness non-adiabatic transitions. These corrections define a set of dressed states that the system follows exactly during the state transfer. We apply this approach to STIRAP protocols and show that a suitable choice of dressed states allows one to design fast protocols that do not require additional couplings, while simultaneously minimizing the occupancy of the "intermediate" level.
Non-adiabatic decay rates for a radio-frequency dressed magnetic trap are calculated using Fermi's Golden Rule: that is, we examine the probability for a single atom to make transitions out of the dressed trap and into a continuum in the adiabatic limit, where perturbation theory can be applied. This approach can be compared to the semi-classical Landau-Zener theory of a resonant dressed atom trap, and it is found that, when carefully implemented, the Landau-Zener theory overestimates the rate of non-adiabatic spin flip transitions in the adiabatic limit. This indicates that care is needed whe…
Generation of multi-photon Fock states by bichromatic adiabatic passage: topological analysis
利用绝热通过技术和修饰本征能面的拓扑性质，提出了一种在原子-脉泽-腔系统中产生多光子Fock态的方案。其机制是通过双色绝热通道将来自脉泽场的光子交换到初始空腔中。交换光子的数量取决于通过和周围的装饰本征能表面的锥形交叉点的绝热动力学的设计。
We present a scheme to realize multiple-qubit quantum state transfer and quantum logic gate by combining the advantages of Vitanov-style pulses and dressed-state-based shortcut to adiabaticity (STA) in Rydberg atoms. The robustness of the scheme to spontaneous emission can be achieved by reducing the population of Rydberg excited states through the STA technology. Meanwhile, the control errors can be minimized through using the well-designed pulses. Moreover, the dressed-state method applied in the scheme makes the quantum state transfer more smoothly turned on or off with high fidelity and al…
We study an architecture for implementing adiabatic quantum computation with trapped neutral atoms. Ground state atoms are dressed by laser fields in a manner conditional on the Rydberg blockade mechanism, thereby providing the requisite entangling interactions. As a benchmark we study the performance of a Quadratic Unconstrained Binary Optimization (QUBO) problem whose solution is found in the ground state spin configuration of an Ising-like model. We model a realistic architecture, including details of the atomic implementation, with qubits encoded into the clock states of 133Cs, effective B…
Exploring quantum technology to precisely measure physical quantities is a meaningful task for practical scientific researches. Here, we propose a novel quantum sensing model based on dressed states driving (DSD) in stimulated Raman adiabatic passage. The model is universal for sensing different physical quantities, such as magnetic field, mass, rotation and etc. For different sensors, the used systems can range from macroscopic scale, e.g. optomechanical systems, to microscopic nanoscale, e.g. nitrogen-vacancy color centres in diamond. By investigating the dynamics of color detuning of DSD pa…
In this paper, we propose a protocol to prepare W states with superconducting quantum interference devices (SQUID) by using dressed states. Through choosing a set of dressed states suitably, the protocol can be used to accelerate the adiabatic passages while additional couplings are unnecessary. Moreover, we can optimize the evolution of the system with the restraint to the populations of the intermediate states by choosing suitable controlled parameters. Numerical simulations show that the protocol is robust against the parameter variations and decoherence mechanisms. Furthermore, the protoco…
A highly feasible dressed-state scheme, which greatly speeds up the adiabatic population transfer of a quantum system, is applied for implementing a fast CNOT gate in a cavity QED system. The cavity QED system consists of two identical five-level atoms which are respectively trapped in two optical cavities connected by a fiber. With the help of quantum Zeno dynamics, the CNOT gate is constructed by three steps with six pulses. Because the adiabatic condition is not necessary to be considered and all of the pulses are smoothly turned on and off, the scheme is fast and feasible in experiment. Nu…
Counterdiabatic Driving under Variational Frame Dressing
该研究提出变分修饰框架下的反绝热驱动方法，通过推导通用映射形式体系，实现了可在实验室原生控制下执行的反绝热协议，解决了传统反绝热驱动难以物理实现的问题。
Ultracold atoms in radio-frequency-dressed potentials beyond the rotating wave approximation
在原子芯片射频阱中研究了缀饰玻色-爱因斯坦凝聚体。我们表明，在这个系统中，可以实现足够强的敷料，导致广泛使用的旋转波近似（RWA）打破。我们提出了一个完整的计算的原子-场耦合表明，非RWA的贡献定量地改变了新兴的修饰绝热势的形状。此外，非RWA贡献导致额外的允许的过渡之间的修饰电平。我们利用射频光谱的玻色-爱因斯坦凝聚体被困在修饰态势直接观察从RWA到超越RWA制度的转变。
In this paper we review different aspects of the dynamical Casimir- Polder potential between a neutral atom and a perfectly conducting plate under nonequilibrium conditions. In order to calculate the time evolution of the atom-wall Casimir-Polder potential, we solve the Heisenberg equations describing the dynamics of the coupled system using an iterative technique. Different nonequilibrium initial states are considered, such as bare and partially dressed states. The partially dressed states considered are obtained by a sudden change of a physical parameter of the atom or of its position relati…
Strong coupling of molecules to the vacuum field of micro cavities can modify the potential energy surfaces opening new photophysical and photochemical reaction pathways. While the influence of laser fields is usually described in terms of classical field, coupling to the vacuum state of a cavity has to be described in terms of dressed photon-matter states (polaritons) which require quantized fields. We present a derivation of the non-adiabatic couplings for single molecules in the strong coupling regime suitable for the calculation of the dressed state dynamics. The formalism allows to use qu…
Implementing a Universal Set of Geometric Quantum Gates through Dressed-State assisted STA
本文提出利用受激态框架中的超亚adiabatic无驱动协议实现快速高保真度的几何量子门，通过NV中心在微波场下的两能级系统实现单量子门，并扩展至非平凡双量子门，展示其在可扩展量子信息处理中的可行性。
A semiclassical, four-level model of a nanosecond, chirped pulse interacting with all optically accessible hyperfine states in the ultracold Rb atom is analyzed aiming at population inversion within $5S_{1/2}$ electronic state. The nature of two-photon adiabatic passage performed by such a single pulse having a bandwidth smaller than the hyperfine splitting of $5S_{1/2}$ state is investigated in the framework of the dressed state picture. It is shown that two dressed states are involved in the adiabatic dynamics of population inversion. The excited state manifold appeared to play an important …
We present a novel representation of coupled matter-photon systems that allows the application of many-body methods developed for purely fermionic systems. We do so by rewriting the original coupled light-matter problem in a higher-dimensional configuration space and then use photon-dressed orbitals as a basis to expand the thus "fermionized" coupled system. As an application we present a dressed time-dependent density-functional theory approach. The resulting dressed Kohn-Sham scheme allows for straightforward non-adiabatic approximations to the unknown exchange-correlation potential that exp…
We present a new paradigm in the field of cavity QED by bringing out remarkable features associated with the avoided crossing of the dressed state levels of the Jaynes Cummings model. We demonstrate how the parametric couplings, realized by a second order nonlinearity in the cavity, can turn the crossing of dressed states into avoided crossings. We show how one can generate coherence between the avoided crossing of dressed states. Such coherences result, for example, in quantum beats in the excitation probability of the qubit. The quality of quantum beats can be considerably improved by adiaba…
The studies on quantum open system play key roles not only in fundamental problems in quantum mechanics but also in quantum computing and information processes. Here we propose a scheme to use a one dimensional coupling cavity array (CCA) as an artificial electromagnetic environment of a two-level atom. For a finite length of CCA, we find that after a turning time the population of excited state deviates suddenly from the exponential decay. We show that physically this phenomena corresponds to a transition from a naked atom decay to a dressed state decay. We hope that our finding will promote …
In this work, we investigate the quantum phase transition of light in the dissipative Rabi-Hubbard lattice under the framework of the mean-field theory and quantum dressed master equation. The order parameter of photons in strong qubit-photon coupling regime is derived analytically both at zero and low temperatures. Interestingly, we can locate the localization and delocalization phase transition very well in a wide parameter region. {In particular for the zero-temperature limit, the critical tunneling strength approaches zero generally in the deep-strong qubit-photon coupling regime, regardle…
We study the dynamic sensitivity of an atomic ensemble dressed by a single-mode cavity field (called a photon-dressed atomic ensemble), which is described by the Dicke model near the quantum critical point. It is shown that when an extra atom in a pure initial state passes through the cavity, the photon-dressed atomic ensemble will experience a quantum phase transition, showing an explicit sudden change in its dynamics characterized by the Loschmidt echo of this quantum critical system. With such dynamic sensitivity, the Dicke model can resemble to the cloud chamber for detecting a flying part…
Quantum Superposition, Collapse of Wave Function, Quantum Measurement and Nonadiabatic Dressed States
本文基于非绝热缀饰态和实验观测，重新审视量子叠加、波函数坍缩与测量问题，揭示其物理机制。
Cavity induced modifications to the resonance fluorescence and probe absorption of a laser-dressed V atom
在坏腔极限下，导出了相干驱动V型三能级原子与单模腔耦合的腔修正主方程。我们发现，在裸态和修饰态基的粒子数反转可以实现，源于增强的原子-腔相互作用时，腔与原子修饰态跃迁共振。缀饰态表象中的原子布居分析的腔修改的过渡率。对原子荧光光谱和探针吸收光谱进行了研究，发现可以通过调节腔频率来控制其光谱轮廓。在适当的条件下会出现峰值抑制和谱线变窄。
Two-mode squeezing and entanglement is obtained in a atom-cavity system cosisting a three-level atom and a two-mode cavity with driving laser fields. Here non-resonatn dressed-state transitions between the cavity modes and atom are used to get the effective Hamiltonian.
Approximate Master Equations for Atom Optics
在原子光学领域，许多实验都是以二能级原子与光场的耦合为基础的。这个系统的演化是由一个主方程控制的。这个主方程的不可逆分量描述了光子从原子的自发发射。对于许多应用，有必要将这种不可逆演变的影响降至最低。这可以通过具有远失谐光场来实现。这种机制的缺点是，使失谐非常大，使得求解主方程所需的时间步长非常小，比任何重要演化的时间尺度小得多。这使得问题在数值上非常密集。由于这个原因，近似被用来模拟主方程，这是更容易解决的数值。本文分析了四种近似：标准绝热近似;更复杂的绝热近似（以前没有使用过）;长期近似;和全量子修饰态近似。每一个的优点和缺点进行了调查方面的准确性，复杂性和模拟所需的资源。在一个特别实验感兴趣的参数制度，只有复杂的绝热和dressed状态近似同意与确切的演变。
Neutral atoms are building blocks of ground-up quantum many-body systems. Well-controlled and high-fidelity entangling gates are an essential component for realizing complex neutral atom architectures for quantum computing, quantum simulation, and measurement with precision better than the standard quantum limit. In this Letter we report the realization of a Mølmer-Sørensen unitary between two neutral atoms, based on adiabatic single-photon dressing to Rydberg levels. We show that this technique is highly robust to noise sources and experimental imperfections that have limited the fidelity of …
Radio-frequency induced ground state degeneracy in a Chromium Bose-Einstein condensate
我们研究了强射频场对铬玻色-爱因斯坦凝聚体（BEC）的影响，在一个制度中，射频频率远大于拉莫尔频率。我们使用修改的Landé因子的射频场，使所有的塞曼状态的简并，尽管存在的静态磁场高达100 mG。这是证明通过分析的影响下，在强场制度的修饰磁势的原子的轨迹。我们调查的射频敷料过程中的绝热性的问题，并将其与如何接近的敷料状态是简并。最后，我们测量了射频修饰玻色电晶体的寿命，并确定了一个新的射频辅助的偶极-偶极相互作用引起的两体损耗过程。
Dressed Qubits
在量子计算中，当实际系统的哈密顿量或希尔伯特空间偏离所需的哈密顿量或希尔伯特空间时，会产生固有的门误差。两个重要的例子，我们地址的自旋耦合量子点的存在下的自旋轨道扰动的海森堡交换相互作用，和非共振跃迁的量子位嵌入在一个多层次的希尔伯特空间。我们提出了一个“穿着量子位”的转换来处理这样的固有错误。与量子纠错不同，修饰量子比特方法不需要额外的操作或编码冗余，对误差幅度不敏感，并且不施加新的实验约束。
Analog quantum simulation of small-polaron physics in arrays of neutral atoms with Rydberg-dressed resonant dipole-dipole interaction
提出基于Rydberg-dressed共振偶极-偶极相互作用的中性原子阵列模拟量子模拟器方案，研究Peierls和呼吸模式型激子-声子相互作用，揭示急剧的小极化子跃迁现象。
We demonstrate the capability of complete thresholdless lasing operation between dressed states of a two-level atom located inside a microscopic cavity engineered in a photonic band-gap material. We distinguish between threshold and thresholdless behaves by analyzing the Mandel's Q parameter for the cavity field. We find that the threshold behave depends on whether the spontaneous emission is or is not present on the lasing transition. In the presence of the spontaneous emission, the mean photon number of the cavity field exhibits threshold behavior indicating that the system may operate as an…
We present the model of one-dimensional chain of two-level artificial atoms driven with dc field and quantum light simultaneously in strong coupling regime. The interaction of atoms with light leads to entanglement of electron and photon states (dressing of the atoms). The driving via dc field leads to the Bloch oscillations (BO) in the chain of dressed atoms. We considered the mutual influence of dressing and BO and show that scenario of oscillations dramatically differs from predicted by the Jaynes-Cummings and Bloch-Zener models. We study the evolution of the population inversion, tunneling…
Using a Direct Simulation Monte Carlo technique, we have studied the time evolution of a cold atom cloud interacting with a time dependent radio frequency (rf) dressed state potential. Exposure of a cloud of $^{87}Rb$ atoms, trapped in a quadrupole magnetic trap, to a time dependent rf-field with increasing amplitude and decreasing frequency, shows a variation in the number of trapped atoms and the overall shape of the atom cloud. It is shown by simulations that, initially at lower rf-field strength, the rf-field results in ejection of atoms from the trap, leading to evaporative cooling of the…
Robust adiabatic approach to optical spin entangling in coupled quantum dots
激子跃迁为耦合纳米结构中的超快光学自旋操纵提供了一条可能的途径。本文详细研究了耦合量子点中光控电子自旋量子比特的三种主要激子介导的退相干通道：激子态的辐射衰减、激子-声子相互作用和激光修饰态之间的朗道-齐纳跃迁。我们考虑一个计划，以产生一个纠缠控制相位门上的一对耦合自旋，在其最简单的动态形式，使系统受到快速退相干率与激子创建期间的门操作。相比之下，我们表明，采用非共振激光激发的绝热方法，使我们能够同时抑制所有的退相干源，显着增加的保真度的操作，只有一个相对较小的门控时间成本。我们发现，精确到10^2分之一的受控相位门可以用绝热方法实现，而传统的动态方法似乎不支持适用于可扩展量子计算的保真度。我们的预测可以在不久的将来得到实验验证。
We investigate theoretically quantum effects of a cavity-atom system in which the upper two levels of a cascade-type three-level atom interact with a cavity field mode in the ultrastrong coupling regime. By exploiting the virtual photons carried by atom-cavity dressed states, we indicate how two external driving fields induce Raman transitions such that a continuous conversion of virtual photons into real photons can be achieved with a high probability. We present analytical and numerical solutions of the system. In addition, we show that the converted photons exhibit a bunching behavior in th…
Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a Nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we …
The molecular association process in a thermal gas of $^{85}$Rb is investigated where the effects of the envelope of the radio-frequency field are taken into account. For experimentally relevant parameters our analysis shows that with increasing pulse length the corresponding molecular conversion efficiency exhibits low-frequency interference fringes which are robust under thermal averaging over a wide range of temperatures. This dynamical interference phenomenon is attributed to Stückelberg phase accumulation between the low-energy continuum states and the dressed molecular state which exhibi…
For a finite XY chain and a finite two-dimensional Ising lattice, it is shown that the paramagnetic ground state is adiabatically transformed to the GHZ state in the ferromagnetic phase by slowly turning on the magnetic field. The fidelity between the GHZ state and an adiabatically evolved state shows a feature of the quantum phase transition.
Virtual mitigation of coherent non-adiabatic transitions by echo verification
本文提出绝热回波验证协议，通过准绝热正反向演化抑制非绝热跃迁和硬件噪声引起的错误，仅用正时间动力学即可将可观测量估计偏差较标准绝热制备降低至二次方改进。
We experimentally studied the microwave response of a transmon artificial atom coupled to two closely spaced resonant modes. When the atom is under driven with one of the modes, the atom state and mode photons are superposed, forming the dressed states. Dressed states with 1st, 2nd and 3rd excited states of the atom were prepared and probed via the strong coupling to the other resonant mode from the point of view of cavity quantum electrodynamics. The transmission of the probe tone is modulated by the driving microwave amplitude, displaying multi-photon process associated with the inter-atomic…
We consider the fundamental problem of high temperature phase transitions in the system of high density two-level atoms off-resonantly interacting with a pump field in the presence of optical collisions (OCs) and placed in the cavity. OCs are considered in the framework of thermalization of atomic dressed state (DS) population. For the case of a strong atom-field coupling condition we analyze the problem of thermodynamically equilibrium superradiant phase transition for the order parameter representing a real amplitude of cavity mode and taking place as a result of atomic DSs thermalization pr…
We investigate spatial adiabatic passage of a Bose-Einstein condensate in a triple well potential within the three-mode approximation. By rewriting the dynamics in the so-called time-dependent dark/dressed basis, we analytically derive the optimal conditions for the non-linear parameter and the on-site energies of each well to achieve a highly efficient condensate transport. We show that the non-linearity yields a high-efficiency plateau for the condensate transport as a function of the on-site energy difference between the outermost wells, favoring the robustness of the transport. We also ana…
Semiclassical dressed states of two-level quantum systems driven by nonresonant and/or strong laser fields
本文给出了在非共振和强激光场驱动下的相干态二能级量子系统的半经典缀饰态和相应的准能量的解析表达式。这些表达式在适当的微扰展开中是一阶的，并且已经包含了这些系统在这种特定条件下所显示的动力学和光谱特性的所有相关物理信息。激光场参数对跃迁频率、选择规则和谱线强度的影响可以通过准能级图和不同半经典修饰态之间的允许跃迁来容易地理解。
Strain-Induced Detuning of a Dressed Nitrogen-Vacancy Qubit: Effective Two-Level Theory and Its Validity
研究金刚石中应变对缀饰氮空位量子比特影响，通过微扰消除旁观态推导有效二能级模型，得出相关闭式表达式，展示应变对量子比特的效应，推导有效性标准并简化为准则，为设计传感实验提供指南。
Multi-Frequency Coherence Control of Radio-Frequency-Dressed States
本文通过射频缀饰态中的多频率微波场工程化，实现了铷原子窄跃迁的磁场依赖性抑制，适用于冷原子相干叠加方案。
In this chapter we review the field of radio-frequency dressed atom trapping. We emphasise the role of adiabatic potentials and give simple, but generic models of electromagnetic fields that currently produce traps for atoms at microkelvin temperatures and below. The paper aims to be didactic and starts with general descriptions of the essential ingredients of adiabaticity and magnetic resonance. As examples of adiabatic potentials we pay attention to radio-frequency dressing in both the quadrupole trap and the Ioffe-Pritchard trap. We include a description of the effect of different choices o…
We demonstrate a method for preparing and detecting all eigenstates of a three-level microwave dressed system with a single trapped ion. The method significantly reduces the experimental complexity of gate operations with dressed-state qubits, as well as allowing all three of the dressed-states to be prepared and detected, thereby providing access to a qutrit that is well protected from magnetic field noise. In addition, we demonstrate individual addressing of the clock transitions in two ions using a strong static magnetic field gradient, showing that our method can be used to prepare and det…
We report on experiments exploring the non-Hermitian dynamics of pairs of two-level atoms tightly confined in an optical lattice and driven by a near-resonant laser. Although spontaneous emission is negligible for the long-lived excited state, two-body dissipation arises from strong inelastic collisions between two atoms in the excited state. We demonstrate quasi-adiabatic control of the internal state of the pairs in the quantum Zeno regime where inelastic losses dominate. Preparing each atom pair in the longest-lived eigenstate of the non-Hermitian Hamiltonian describing the dissipative dyna…
Dissipative dynamics and superradiant countinuous time crystal in a Rydberg-interacting Dicke system
研究Rydberg-修饰Dicke系统中耗散与相互作用的相互作用，揭示其非平衡动力学及超辐射连续时间晶体相的形成机制。
Dressed spin states, a spin coupling to continuous radiation fields, can fundamentally change how a spin responds to magnetic fluctuations. Using dressed spin states, we were able to protect an electron spin in diamond from decoherence. Dressing a spin with resonant microwaves at a coupling rate near 1 MHz leads to a 50 times reduction in the linewidth of the spin transition, limited by transit-time broadening. The spin decoherence and the energy level structure of the dressed states were probed with optical coherent-population-trapping processes. Compared with dynamical decoupling, where effe…
We propose a theoretical approach for the interpretation of pump-probe measurements where an attosecond pulse is absorbed in the presence of an intense laser pulse. This approach is based on abstractly defined dressed bound states, which capture the essential aspects of the interaction with the laser pulse and facilitate a perturbative description of transitions induced by the attosecond pulse. Necessary properties of dressed bound states are defined and various choices are discussed and compared to accurate numerical solutions of the time-dependent Schroedinger equation.
A cavity quantum electrodynamical (QED) system beyond the strong-coupling regime is expected to exhibit intriguing quantum phenomena. Here we report a direct measurement of the photon-dressed qubit transition frequencies up to four photons by harnessing the same type of state transitions in an ultrastrongly coupled circuit-QED system realized by inductively coupling a superconducting flux qubit to a coplanar-waveguide resonator. This demonstrates a convincing observation of the photon-dressed Bloch-Siegert shift in the ultrastrongly coupled quantum system. Moreover, our results show that the p…
We report the first experimental demonstration of interference-induced spectral line elimination predicted by Zhu and Scully [Phys. Rev. Lett. 76, 388 (1996)] and Ficek and Rudolph [Phys. Rev. A 60, 4245 (1999)]. We drive an exciton transition of a self-assembled quantum dot in order to realize a two-level system exposed to bichromatic laser field and observe nearly complete elimination of the resonance fluorescence spectral line at the driving laser frequency. This is caused by quantum interference between coupled transitions among the doubly dressed excitonic states, without population trapp…
Coherent control of dressed matter waves
通过快速上下移动摆的支点，人们可以创造一个稳定的位置，摆锤在支点上方而不是下方。这种令人惊讶和违反直觉的现象是驱动系统的普遍特征，并延续到量子世界。即使量子系统的静态性质是已知的，它对参数随时间变化的响应也可能是非常重要的，并且可以出现在原始系统中不存在的定性新状态。在量子力学中，这种行为的原型是辐射场中的原子，它表现出许多基本现象，例如射频场中g因子的改变以及作用在原子上的偶极力在空间变化的光场中运动。这些效应可以成功地描述在所谓的缀饰原子图片。在这里，我们表明，敷料的概念也可以应用到宏观物质波，和“打扮物质波“的量子态可以相干控制。在我们的实验中，我们使用玻色-爱因斯坦凝聚体在驱动的光晶格，并证明了该系统的多体状态可以通过改变驱动的振幅，在超流和莫特绝缘状态之间的可逆和可逆的变化。我们的设置代表了一个多功能的测试场驱动量子系统，我们的结果表明新的量子控制方案的方向物质波。
Implementing a scalable quantum information processor using polar molecules in optical lattices requires precise control over the long-range dipole-dipole interaction between molecules in selected lattice sites. We present here a scheme using trapped open-shell $^2Σ$ polar molecules that allows dipolar exchange processes between nearest and next-nearest neighbors to be controlled to construct a generalized transverse Ising spin Hamiltonian with tunable $XX$, $YY$ and $XY$ couplings in the rotating frame of the driving lasers. The scheme requires a moderately strong bias magnetic field with nea…
We report on the realization of long-range Ising interactions in a cold gas of cesium atoms by Rydberg dressing. The interactions are enhanced by coupling to Rydberg states in the vicinity of a Förster resonance. We characterize the interactions by measuring the mean-field shift of the clock transition via Ramsey spectroscopy, observing one-axis twisting dynamics. We furthermore emulate a transverse-field Ising model by periodic application of a microwave field and detect dynamical signatures of the paramagnetic-ferromagnetic phase transition. Our results highlight the power of optical address…
This paper presents a method of computing approximate conservation laws and eigenstates of integrability-broken models using the concept of adiabatic continuation. Given some Hamiltonian, eigenstates and conserved operators may be computed by using those of a simple Hamiltonian close by in parameter space, dressed by some unitary rotation. However, most adiabatic continuation analyses only use this unitary implicitly. In this work, approximate adiabatic gauge potentials are used to construct a state dressing using variational methods, to compute eigenstates via a rotated truncated spectrum app…
A method to interpret probe spectra of driven degenerate atomic systems is discussed. The dressed-atom multiphoton spectroscopy (DAMS) is based on a dressing of the atomic system with the strong coupling field, followed by a perturbative treatment of the probe field interaction. As example, we apply the DAMS to provide a clear interpretation for anomalous electromagnetically induced absorption (EIA), which cannot be explained by spontaneous transfer of coherence. We show that anomalous EIA arises from quantum interference between competing two-photon transitions, and explain the different depe…
The quantum superposition principle: a reconsideration
该研究基于量子力学绝热定理、非绝热缀饰态及实验证据重新审视量子叠加原理，揭示了其物理机制与特性，深化了对量子叠加的认知。
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