The recent baryon acoustic oscillation (BAO) measurements from the dark energy spectroscopic instrument (DESI) have sharpened one of the central questions in modern cosmology: whether cosmic acceleration is driven by a true cosmological constant or by new physics in the dark sector, gravity, or the early Universe. Although DESI BAO data alone remain broadly consistent with flat Λ cold dark matter model, their combination with cosmic microwave background and supernova observations shows a moderate preference for an evolving dark-energy equation of state, often associated with effective phantom-crossing behavior. This preference should not be interpreted as a definitive detection of a time-varying dark-energy fluid. Rather, it exposes a broader degeneracy among late-time dynamical dark energy, dark-sector interactions, modified gravity, early-Universe sound-horizon calibration, neutrino-mass inference and residual systematics. In this review, we summarize the post-DESI status of dark-energy research, emphasizing both the significance and the limitations of the present evidence. We discuss dynamical dark energy as an effective description of the expansion history, compare it with interacting dark-energy and modified-gravity interpretations, and examine how the Hubble tension, the S8 tension and cosmological neutrino-mass constraints act as joint consistency tests of the underlying framework. We further highlight the role of future geometry, growth, absolute-distance and baryon-distribution probes, together with reproducible multi-probe likelihoods, in distinguishing physical mechanisms from statistical fluctuations and residual systematics. We argue that the post-DESI era is shifting dark-energy research from parameter fitting toward multi-sector physical diagnosis.
Precision spectroscopy, a fundamental tool in both fundamental science and practical applications, is inevitably subject to several detrimental effects. Here we propose a symmetry-protected destructive many-body interferometry (SPDMBI) for precision spectroscopy, which successfully mitigates the spectral shifts caused by interparticle interaction, noise, decoherence and experimental imperfection. Through matching the symmetry of the input states and the Hamiltonian, the SPDMBI-based precision spectroscopy yields an antisymmetric spectrum, whose antisymmetric point exactly determines the resonance frequency. In such a precision spectroscopy, the population difference under resonance is always zero, which is a result of the destructive many-body quantum interferometry. To demonstrate its versatility, we showcase successful applications of symmetry-protected Rabi and Ramsey spectroscopy in measuring both time-independent and time-dependent signals. Our protocol improves the performance of precision spectroscopy and offers a pathway for various high-precision quantum sensors.
Gravitational microlensing in strongly lensed active galactic nuclei (AGNs) provides a powerful probe of accretion-disk structure and may offer a unique opportunity to identify sub-parsec supermassive binary black holes (SMBBHs) through distinctive signatures. Upcoming wide-field surveys are expected to discover a large sample of strongly lensed AGNs, a fraction of which may host SMBBHs detectable via microlensing. In this paper, we employ semi-analytic models to assess the detection prospects of sub-parsec SMBBHs in lensed AGNs, focusing on systems with resolvable multiple images suitable for microlensing analysis. Accounting for galaxy-scale strong-lensing statistics, and including the cluster-lensing contribution as an optimistic statistical extension, we estimate that up to approximately 87 such systems could be spatially resolved by individual upcoming surveys, including the Vera C. Rubin Observatory (Rubin), Euclid, China’s Space Survey Telescope (CSST), and the Nancy Grace Roman Space Telescope (Roman). For the Rubin Wide-Fast-Deep survey, we estimate that periodic oscillations in microlensing light curves could identify ∼0.12–0.68 short-period (<5 yr) binaries, whereas diagnostics based on the reconstructed size-wavelength relation apply to a broader population, potentially identifying ∼0.4–5.3 systems, depending on the model assumptions. CSST, Euclid, and Roman may also reveal up to 10.6, 8.9, and 1.2 systems exhibiting size-wavelength features, and 2.3, 1.9, 0.3 systems showing periodic oscillations, which should be regarded as imaging-selected candidates whose microlensing-based identification requires adequate time-domain follow-up, including cadence, monitoring baseline, photometric precision, and reliable time-delay measurements. Our results show that strongly lensed AGNs provide a promising, though observationally demanding, pathway for finding candidate SMBBHs via microlensing.
While atomic intercalation can effectively modify or optimize the properties of transition metal dichalcogenides (TMDs), high pressure can directly impact their structures, enrich their electronic states, and promote the discovery of intriguing phenomena. Here, the high-capacity Cu intercalated 2H-TaS2 was investigated up to 50 GPa. A dramatic change in the c/a ratio was first observed around 6.0 GPa and was confirmed to induce a Lifshitz transition, altering the Fermi surface topology. In addition, the synergistic effect of Cu intercalation and pressure in TaS2 leads to layer sliding, ultimately resulting in the phase transition of Cu0.65TaS2 from 2H (P63/mmc) to 2H ' (P63/mmc) phase at 11.9 GPa. Both 2H- and 2H '-Cu0.65TaS2 maintained metallic character without superconductivity, establishing a fundamental distinction from its parent system, 2H-TaS2. It is unexpected that a charge density wave (CDW) phase transition, driven by the Lifshitz transition, was observed at 5.3 GPa based on temperature-dependent resistance data. Further compression enhanced the transition temperature (T CDW) from 179 K at 5.3 GPa to 286 K (nearing room temperature) at 18.4 GPa. The combination of high-capacity intercalation and high pressure has revealed exotic phenomena that neither method alone can achieve, offering a practical way to develop new materials for different application scenarios.
