37 research outputs found
Cooperative Spin Amplification
Quantum amplification is recognized as a key resource for precision
measurements. However, most conventional paradigms employ an ensemble of
independent particles that usually limit the performance of quantum
amplification in gain, spectral linewidth, etc. Here we demonstrate a new
signal amplification using cooperative 129Xe nuclear spins embedded within a
feedback circuit, where the noble-gas spin coherence time is enhanced by at
least one order of magnitude. Using such a technique, magnetic field can be
substantially pre-enhanced by more than three orders and is in situ readout
with an embedded 87Rb magnetometer. We realize an ultrahigh magnetic
sensitivity of 4.0 fT/Hz that surpasses the photon-shot noise and even
below the spin-projection noise of the embedded atomic magnetometer, allowing
for exciting applications including searches for dark matter with sensitivity
well beyond supernova constraints. Our findings extend the physics of quantum
amplification to cooperative spin systems and can be generalized to a wide
variety of existing sensors, enabling a new class of cooperative quantum
sensors.Comment: 7 pages, 4 figure
Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators
Recent advances in nonlinear optics have revolutionized integrated photonics, providing on-chip solutions to a wide range of new applications. Currently, state of the art integrated nonlinear photonic devices are mainly based on dielectric material platforms, such as Si₃N₄ and SiO₂. While semiconductor materials feature much higher nonlinear coefficients and convenience in active integration, they have suffered from high waveguide losses that prevent the realization of efficient nonlinear processes on-chip. Here, we challenge this status quo and demonstrate a low loss AlGaAs-on-insulator platform with anomalous dispersion and quality (Q) factors beyond 1.5 × 10⁶. Such a high quality factor, combined with high nonlinear coefficient and small mode volume, enabled us to demonstrate a Kerr frequency comb threshold of only ∼36 µW in a resonator with a 1 THz free spectral range, ∼100 times lower compared to that in previous semiconductor platforms. Moreover, combs with broad spans (>250 nm) have been generated with a pump power of ∼300 µW, which is lower than the threshold power of state-of the-art dielectric micro combs. A soliton-step transition has also been observed for the first time in an AlGaAs resonator
SAPPHIRE: Search for exotic parity-violation interactions with quantum spin amplifiers
Quantum sensing provides sensitive tabletop tools to search for exotic
spin-dependent interactions beyond the Standard Model, which has attracted
great attention in theories and experiments. Here we develop a technique based
on quantum Spin Amplifier for Particle PHysIcs REsearch (SAPPHIRE) to
resonantly search for exotic interactions, specifically parity-odd spin-spin
interactions. The present technique effectively amplifies the pseudomagnetic
field generated by exotic interactions by a factor of about 200 while being
insensitive to spurious external magnetic fields. Our studies, using such a
quantum amplification technique, open the doors to exploring the
parity-violation interactions mediated by Z' bosons in the challenging
parameter space (force range between 3 mm and 0.1 km) and set the most
stringent constraints on Z'-mediated electron-neutron couplings, significantly
improving previous limits by up to five orders of magnitude. Moreover, our
bounds on Z'-mediated couplings between nucleons reaches into a hitherto
unexplored parameter space (force range below 1 m), complementing the existing
astrophysical and laboratory studies.Comment: 8 pages, 5 figure
Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators
We demonstrated ultra-efficient frequency comb generation in AlGaAs-on-insulator ring resonators that have a quality factor beyond 1.5*10⁶. The threshold power is as low as 36 µW
Ultra-efficient frequency comb generation in AlGaAs-on-insulator microresonators
Recent advances in nonlinear optics have revolutionized integrated photonics, providing on-chip solutions to a wide range of new applications. Currently, state of the art integrated nonlinear photonic devices are mainly based on dielectric material platforms, such as Si₃N₄ and SiO₂. While semiconductor materials feature much higher nonlinear coefficients and convenience in active integration, they have suffered from high waveguide losses that prevent the realization of efficient nonlinear processes on-chip. Here, we challenge this status quo and demonstrate a low loss AlGaAs-on-insulator platform with anomalous dispersion and quality (Q) factors beyond 1.5 × 10⁶. Such a high quality factor, combined with high nonlinear coefficient and small mode volume, enabled us to demonstrate a Kerr frequency comb threshold of only ∼36 µW in a resonator with a 1 THz free spectral range, ∼100 times lower compared to that in previous semiconductor platforms. Moreover, combs with broad spans (>250 nm) have been generated with a pump power of ∼300 µW, which is lower than the threshold power of state-of the-art dielectric micro combs. A soliton-step transition has also been observed for the first time in an AlGaAs resonator
Effect of progestin on thyroid function in female Wistar rats
IntroductionTo characterize the influence of female-specific hormones on women’s thyroid function, the study investigated the influence of extra progestin from oral contraceptives on inducing thyroid dysfunction.MethodsSixty female Wistar rats were divided into six groups based on levonorgestrel or desogestrel administration as the main active agents: control, low (0.0039 mg*20-fold), medium (0.0039 mg*100-fold), high (0.0318 mg*100-fold) levonorgestrel (pure product); and low (0.0083 mg*20-fold) and high (0.0083 mg*100-fold) desogestrel (pure product). Progestin was administered by gavage every 4 days for 1 month. Statistical analysis was performed using one-way analysis of variance and the Kruskal–Wallis test.ResultsFollowing levonorgestrel gavage, serum free T4 and thyroidstimulating hormone levels were significantly lower in the experimental group than that in the control group (p=0.013 and 0.043). After desogestrel gavage, the serum free T4 and free T3 levels were lower in the experimental group than that in the control group (p=0.019 and 0.030). Thyroid hormone antibody concentrations were lower in rats administered levonorgestrel and desogestrel than that in control rats. Moreover, exposure to progestin upregulated the expression of the thyroid-stimulating hormone receptor and sodium iodide symporter in thyroid.DiscussionProgestin stimulation enhanced the proliferation of follicular epithelial cells in rat thyroid tissues. Progestin exposure could cause thyroid dysfunction by upregulating the transcription of thyroid-stimulating hormone receptor and sodium iodide symporter in thyroid, thus inducing pathomorphological changes in rats’ thyroid
Floquet maser
The invention of the maser stimulated many revolutionary technologies such as
lasers and atomic clocks. Despite enormous progress, the realizations of masers
are still confined to a limited variety of systems, in particular, the physics
of masers remains unexplored in periodically driven (Floquet) systems, which
are generally defined by time-periodic Hamiltonians and enable to observe many
exotic phenomena such as time crystals. Here we investigate the Floquet system
of periodically driven 129Xe gas under damping feedback, and surprisingly
observe a multi-mode maser that oscillates at frequencies of transitions
between Floquet states. Our findings extend maser techniques to Floquet
systems, and open a new avenue to probe Floquet phenomena unaffected by
decoherence, enabling a new class of maser sensors. As a first application, our
maser offers a unique capability of measuring low-frequency (1-100 mHz)
magnetic fields with femtotesla-level sensitivity, which is significantly
better than state-of-the-art magnetometers, and can be immediately applied to,
for example, ultralight dark matter searches.Comment: 26 pages, 4 figure
Search for axion-like dark matter with spin-based amplifiers
Ultralight axion-like particles (ALPs) are well-motivated dark matter
candidates introduced by theories beyond the standard model. However, the
constraints on the existence of ALPs through existing laboratory experiments
are hindered by their current sensitivities, which are usually weaker than
astrophysical limits. Here, we demonstrate a new quantum sensor to search for
ALPs in the mass range that spans about two decades from 8.3 feV to 744 feV.
Our sensor makes use of hyperpolarized long-lived nuclear spins as a
pre-amplifier that effectively enhances coherently oscillating axion-like
dark-matter field by a factor of >100. Using spin-based amplifiers, we achieve
an ultrahigh magnetic sensitivity of 18 fT/Hz, which is significantly
better than state-of-the-art nuclear-spin magnetometers. Our experiment
constrains the parameter space describing the coupling of ALPs to nucleons over
our mass range, at 67.5 feV reaching
( confidence level), improving over previous laboratory limits by at
least five orders of magnitude. Our measurements also constrain the ALP-nucleon
quadratic interaction and dark photon-nucleon interaction with new limits
beyond the astrophysical onesComment: 8 pages, 4 figure