arXiv subjects

Jiteng Sheng

Publications and source records attributed to Jiteng Sheng.

At least 19 recordsLinked to original sources

arXiv2026

Floquet-sideband-enhanced shortwave electrometry with Rydberg atoms

Rydberg atomic electric-field sensors, under the framework of optical excitation and readout, can overcome the size-to-wavelength constraint imposed by the Chu limit. However, their sensitivity for decametric-wavelength shortwave electric fields is substantially lower than that for microwave ones, stemming from the off-resonant nature of low-frequency signals with Rydberg transitions. Here, we demonstrate a high-sensitivity heterodyne shortwave sensor based on microwave-dressed Rydberg atoms, leveraging precisely modulated Floquet sidebands. Around local- and microwave-field-engineered Floquet sidebands, the steep response gradient, arising from the enhanced atom-shortwave interaction through additionally created coherent channels, induces pronounced amplification of the heterodyne intermediate-frequency signal. As a result, compared to the same atomic heterodyne setup without microwave modulation, such Floquet-sideband-enhanced shortwave measurement boosts the sensitivity by four orders of magnitude, yielding a sensitivity of -122.7 dBm/Hz for shortwave at 30 MHz. This work offers a potential route to high-sensitive portable shortwave receivers in radio astronomy, radar and long-distance communications.

physics.atom-ph↗

arXiv2026

Phonon heat transport with squeezing-based symmetry breaking

The controllability of phonon thermal transport is fundamental for numerous technologies, from cooling high-performance chips to managing heat in quantum computing. Despite extensive efforts, on-demand, real-time control of phonon heat flow remains elusive, being fundamentally constrained by the temperature gradient. Here we achieve this long-sought phonon heat transport by introducing a novel mechanism using quantum squeezing in a cavity optomechanical system. We find that phonon squeezing of near-ground-state mechanical resonators via an optomechanically induced parametric process breaks the continuous U(1) rotation symmetry in phase space, and consequently the symmetry in the heat current structure. We reveal that heat flow under a constant temperature gradient can be deterministically amplified, reduced, or even reversed, a capability previously unattainable. With phonon squeezing, we achieve over twentyfold amplification of heat flow and reversal within 30 milliseconds. Importantly, quantum discord analysis reveals a direct connection between heat flow reversal and quantum correlation. Our results establish quantum squeezing as a versatile platform for on-demand phononic thermal control, opening avenues for active heat management in quantum devices and thermal logic circuits.

physics.optics↗

arXiv2024

Optomechanical dark-mode-breaking cooling

Optomechanical cooling of multiple degenerate mechanical modes is prevented by the mechanical dark mode due to destructive interference. Here we report the first experimental demonstration of simultaneous cooling of two near-degenerate mechanical modes by breaking the mechanical dark mode in a two-membrane cavity optomechanical system. The dark mode is generated as the system passes the exceptional point of the antiparity-time symmetric scheme. By introducing a second cavity mode for the additional dissipative channel, the dark mode is broken and the total phonon number is reduced by more than an order of magnitude below the dark mode cooling limit. Owing to the flexible tunability of the optomechanical coupling rates of such a four-mode coupled system, the optimized cooling efficiency can be achieved by investigating different parameter ranges. Our results provide an important step towards the ground state cooling and entanglement among multiple degenerate mechanical resonators.

quant-ph↗

arXiv2024

Room temperature single-photon terahertz detection with thermal Rydberg atoms

Single-photon terahertz (THz) detection is one of the most demanding technology for a variety of fields and could lead to many breakthroughs. Although its significant progress has been made in the last two decades, operating it at room temperature still remains a great challenge. Here, we demonstrate, for the first time, the room temperature THz detector at single-photon levels based on nonlinear wave mixing in thermal Rydberg atomic vapor. The low-energy THz photons are coherently upconverted to the high-energy optical photons via a nondegenerate Rydberg state involved six-wave-mixing process, and therefore, the single-photon THz detection is achieved by a conventional optical single-photon counting module. The noise equivalent power of such a detector is reached to be 9.5*10^-19 W/Hz^1/2, which is more than four orders of magnitude lower than the state-of-the-art room temperature THz detectors. The optimum quantum efficiency of the whole wave-mixing process is about 4.3% with 40.6 dB dynamic range, and the maximum conversion bandwidth is 172 MHz, which is all-optically controllable. The developed fast and continuous-wave single-photon THz detector at room temperature operation has a great potential to be portable and chip-scale, and could be revolutionary for a wide range of applications in remote sensing, wireless communication, biomedical diagnostics, and quantum optics.

quant-ph↗

arXiv2023

Anomalous Thermodynamic Cost of Clock Synchronization

Clock synchronization is critically important in positioning, navigation and timing systems. While its performance has been intensively studied in a wide range of disciplines, much less is known for the fundamental thermodynamics of clock synchronization, what limits the precision and how to optimize the energy cost for clock synchronization. Here, we report the first experimental investigation of two stochastic clocks synchronization, unveiling the thermodynamic relation between the entropy cost and clock synchronization in an open cavity optomechanical system. Two autonomous clocks are synchronized spontaneously by engineering the controllable photon-mediated dissipative optomechanical coupling and the disparate decay rates of hybrid modes. The measured dependence of the degree of synchronization on entropy cost exhibits an unexpected non-monotonic characteristic, indicating that the perfect clock synchronization does not cost the maximum entropy and there exists an optimum. The investigation of transient dynamics of clock synchronization exposes a trade-off between energy and time consumption. Our results reveal the fundamental relation between clock synchronization and thermodynamics, and have a great potential for precision measurements, distributed quantum networks, and biological science.

quant-ph↗

arXiv2021

Realization of a coupled-mode heat engine with cavity-mediated nanoresonators

We report an experimental demonstration of a coupled-mode heat engine in a two-membrane-in-the-middle cavity optomechanical system. The normal mode of the cavity-mediated strongly coupled nanoresonators is utilized as the working medium and an Otto cycle is realized by extracting work between two phononic thermal reservoirs. The heat engine performance is characterized in both normal mode and bare mode pictures, which reveals that the correlation of two membranes plays a significant role during the thermodynamic cycle. Moreover, a straight-twin nanomechanical engine is implemented by engineering the normal modes and operating two cylinders out-of-phase. Our results demonstrate an essential class of heat engine for the first time in cavity optomechanical systems and provide a novel platform for investigating heat engines of interacting subsystems in small scales with controllability and scalability.

quant-ph↗

arXiv2021

Dissipative coupling induced phonon lasing with anti-parity-time symmetry

Phonon lasers, as the counterpart of photonic lasers, have been intensively studied in a large variety of systems, however, (all) most of them are based on the directly coherent pumping. Intuitively, dissipation is an unfavorable factor for gain in a laser. Here we demonstrate a novel mechanism of phonon lasing from the dissipative coupling in a multimode optomechanical system. By precisely engineering the dissipations of two membranes and tuning the intensity modulation of the cavity light, the two-membrane-in-the-middle system shows anti-parity-time (anti-PT) symmetry and the cavity mediated interaction between two nanomechanical resonators becomes purely dissipative. The level attraction and damping repulsion are clearly exhibited as the signature of dissipative coupling. After the exceptional point, a non-Hermitian phase transition, where eigenvalues and the corresponding eigenmodes coalesce, two phonon modes are simultaneously excited into the self-sustained oscillation regime by increasing the interaction strength over a critical value (threshold). In distinct contrast to conventional phonon lasers, the measurement of the second-order phonon correlation reveals the oscillatory and biexponential phases in the nonlasing regime as well as the coherence phase in the lasing regime. Our study provides a new method to study phonon lasers in a non-Hermitian open system and could be applied to a wide range of disciplines, including optics, acoustics, and quantum many-body physics.

physics.optics↗

arXiv2020

Phonon heat transport in cavity-mediated optomechanical nanoresonators

The understanding of heat transport in nonequilibrium thermodynamics is an important research frontier, which is crucial for implementing novel thermodynamic devices, such as heat engines and refrigerators. The convection, conduction, and radiation are the well-known basic ways to transfer thermal energy. Here we demonstrate a new mechanism of phonon heat transport between two spatially separated nanomechanical resonators coupled by the cavity-enhanced long-range interactions. The single trajectory for thermalization and non-equilibrium dynamics is monitored in real-time. We find that, in the strong coupling regime, instant heat flux counterintuitively oscillates back and forth in nonequilibrium steady states, which occurs spontaneously above the critical point during the thermal energy transfer process. The universal bound on the precision of nonequilibrium steady-state heat flux, i.e. the thermodynamic uncertainty relation, is verified in such a temperature gradient driven far-off equilibrium system. Our results reveal a previously unobserved phenomenon for heat transfer with mechanical oscillators, and provide a playground for testing fundamental theories in non-equilibrium thermodynamics.

physics.optics↗

arXiv2020

Self-organized synchronization of phonon lasers

Self-organized synchronization is a ubiquitous collective phenomenon, in which each unit adjusts their rhythms to achieve synchrony through mutual interactions. The optomechanical systems, due to their inherently engineerable nonlinearities, provide an ideal platform to study self-organized synchronization. Here, we demonstrate the self-organized synchronization of phonon lasers in a two-membrane-in-the-middle optomechanical system. The probe of individual membrane enables to monitor the real-time transient dynamics of synchronization, which reveal that the system enters into the synchronization regime via torus birth bifurcation line. The phase-locking phenomenon and the transition between in-phase and anti-phase regimes are directly observed. Moreover, such a system greatly facilitate the controllable synchronous states, and consequently a phononic memory is realized by tuning the system parameters. This result is an important step towards the future studies of many-body collective behaviors in multiresonator optomechanics with long distances, and might find potential applications in quantum information processing and complex networks.

physics.optics↗

arXiv2019

Twin-beam-enhanced displacement measurement of a membrane in a cavity

Ultrasensitive measurement of a small displacement is an essential goal in various applications of science and technology, ranging from large-scale laser interferometric gravitational wave detectors to micro-electro-mechanical-systems-based force microscopy. The least measurable displacement is ultimately limited by the quantum nature of light in a classical optical sensor. Here we use the bright quantum correlated light, i.e., twin beams, generated by a coherent atomic medium to surpass the shot-noise limit (SNL) of the displacement measurement of a membrane in an optical cavity. The sensitivity of 200 $am/\sqrt {Hz}$ is achieved, which is more than two orders of magnitude better than a standard Michelson interferometer. An improvement of 3 $dB$ in the signal-to-noise ratio (SNR) beyond the SNL is realized at an equivalent optical power, by using quantum correlated light with noise squeezed 7 $dB$ below the vacuum level. Moreover, the frequency correlation of twin beams is directly measured by using optical cavities, and this relation is utilized to reduce the excess classical noise. Additionally, the displacement measurement sensitivity is further substantially enhanced by the cavity mediated dispersion and the SNR is increased by one order of magnitude compared to the free space case. These results provide a novel strategy for the world of precision measurement as well as to control cavity optomechanical systems with non-classical light.

physics.optics↗

arXiv2018

A controllable two-membrane-in-the-middle cavity optomechanical system

We report an optomechanical system with two dielectric membranes inside a Fabry-Perot cavity. The cavity resonant frequencies are measured in such a two-membrane-in-the-middle system, which show an interesting band-structure-like diagram. This system exhibits great controllability on the parameters of the system. The positions and angles of each membrane can be manipulated on demand by placing two membranes inside the cavity separately. The eigenfrequencies of the vibrational modes of the membranes can also be tuned individually with piezoelectricity. This scheme could be straightforwardly extended to multiple-membrane-in-the-middle systems, where more than two membranes are involved. Such a well controllable multiple membrane optomechanical system provides a promising platform for studying nonlinear and quantum dynamical phenomena in multimode optomechanics with distinct mechanical oscillators.

physics.optics↗

arXiv2017

Parity-time-symmetric optical lattice with alternating gain and loss atomic configurations

Since the spatially extended periodic parity-time (PT) symmetric potential can possess certain unique properties compared to a single PT cell (with only a pair of coupled gain-loss components), various schemes have been proposed to realize periodic PT-symmetric potentials based on optical lattices. Here, we experimentally construct a spatially periodic PT-symmetric optical potential based on gain-loss arrays induced in a coherently-prepared atomic medium. The gain and loss arrays are generated in alternating four-level N-type and three-level $Λ$-type configurations in the same atomic medium, respectively, which do not require discrete diffractions as demonstrated in the previous work [Phys. Rev. Lett. 117, 123601(2016)] and can be easier to realize with more relaxed operating conditions. The dynamical behaviors of the system are investigated by measuring the phase difference between two adjacent gain and loss channels. The demonstrated PT-symmetric optical lattice with easy accessibility and better tunability sets a new stage for further exploiting the peculiar physical properties in periodic non-Hermitian systems.

physics.optics↗

arXiv2017

Mechanical Spectroscopy of Parametric Amplification in a High-Q Membrane Microresonator

We develop a stoichiometric SiN membrane-based optoelectromechanical system, in which the properties of the mechanical resonator can be dynamically controlled by the piezoelectric actuation. The mode splitting is observed in the mechanical response spectra of a phase-sensitive degenerate parametric amplifier. In addition, the quality factor Q of the membrane oscillator in this process is signicantly enhanced by more than two orders of magnitude due to the coherent amplication, reaching a Q factor of ~ 3*10^8 and a f*Q product of ~ 8*10^14 at room temperature. The thermomechanical noise squeezing close to -3 dB limitation is also achieved. This system integrates the electrical, optical and mechanical degrees of freedom without compromising the exceptional material properties of SiN membranes, and can be a useful platform for studying cavity optoelectromechanics.

physics.app-ph↗

arXiv2017

Intracavity Rydberg atom electromagnetically induced transparency using a high finesse optical cavity

We present an experimental study of cavity assisted Rydberg atom electromagnetically induced transparency (EIT) using a high-finesse optical cavity ($F \sim 28000$). Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure of the cavity transmission spectrum is observed when Rydberg EIT is generated inside the cavity. The two symmetrically spaced side peaks are caused by bright-state polaritons, while the central peak corresponds to a dark-state polariton. Anti-crossing phenomenon and the effects of mirror adsorbate electric fields are studied under different experimental conditions. We determine a lower bound on the coherence time for the system of $7.26 \pm 0.06 \,μ$s, most likely limited by laser dephasing. The cavity-Rydberg EIT system can be useful for single photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states amongst many other applications.

physics.atom-ph↗

arXiv2016

Observation of electromagnetically induced Talbot effect in an atomic system

We experimentally demonstrate the Talbot effect resulting from the repeated self-reconstruction of a spatially intensity-modulated probe field under the Fresnel near-field regime. By launching the probe beam into an optically induced atomic lattice (established by interfering two coupling fields) inside a rubidium vapor cell, we can obtain an diffracted probe beam pattern from an formed electromagnetically induced grating (EIG) in a three-level $Λ$-type Doppler-free atomic configuration with the assistance of electromagnetically induced transparency (EIT). The EIG-based diffraction pattern repeats itself at the planes of integer multiple Talbot lengths, which agrees well with the theoretical prediction [Appl. Phys. Lett., 98, 081108 (2011)]. In addition, fractional EIT-induced Talbot effect was also investigated. Such experimentally demonstrated EIT Talbot effect in a coherently-prepared atomic system may pave a way for lensless and nondestructive imaging of ultracold atoms and molecules, and further demonstrating nonlinear/quantum beam dynamical features predicted for established periodic optical systems.

physics.optics↗

arXiv2016

Observation of Parity-Time Symmetry in Optically Induced Atomic Lattices

We experimentally demonstrate PT-symmetric optical lattices with periodical gain and loss profiles in a coherently-prepared four-level N-type atomic system. By appropriately tuning the pertinent atomic parameters, the onset of PT-symmetry breaking is observed through measuring an abrupt phase-shift jump between adjacent gain and loss waveguides. The experimental realization of such readily reconfigurable and effectively controllable PT-symmetric waveguide array structure sets a new stage for further exploiting and better understanding the peculiar physical properties of these non-Hermitian systems in atomic settings.

physics.optics↗

arXiv2016

Atom-Based Sensing of Weak Radio Frequency Electric Fields Using Homodyne Readout

We utilize a homodyne detection technique to achieve a new sensitivity limit for atom-based, absolute radio-frequency electric field sensing of $\mathrm{5 μV cm^{-1} Hz^{-1/2} }$. A Mach-Zehnder interferometer is used for the homodyne detection. With the increased sensitivity, we investigate the dominant dephasing mechanisms that affect the performance of the sensor. In particular, we present data on power broadening, collisional broadening and transit time broadening. Our results are compared to density matrix calculations. We show that photon shot noise in the signal readout is currently a limiting factor. We suggest that new approaches with superior readout with respect to photon shot noise are needed to increase the sensitivity further.

quant-ph↗

arXiv2016

Strong coupling of Rydberg atoms and surface phonon polaritons on piezoelectric superlattices

We propose a hybrid quantum system where the strong coupling regime can be achieved between a Rydberg atomic ensemble and propagating surface phonon polaritons on a piezoelectric superlattice. By exploiting the large electric dipole moment and long lifetime of Rydberg atoms as well as tightly confined surface phonon polariton modes, it is possible to achieve a coupling constant far exceeding the relevant decay rates. The frequency of the surface mode can be selected so it is resonant with a Rydberg transition by engineering the piezoelectric superlattice. We describe a way to observe the Rabi splitting associated with the strong coupling regime under realistic experimental conditions. The system can be viewed as a new type of optomechanical system.

physics.optics↗