中央研究院 原子與分子科學研究所

2025年適逢設所籌備處13年及成所三十週年誌慶，本所特別編輯紀念特刊，紀錄各階段的重要里程碑、人物事蹟與研究成果，藉此完整回顧一路走來的軌跡，保存珍貴的歷史記憶並展望未來。

Nanoscale quantum sensing is playing an increasingly critical role across diverse areas of research, particularly in the rapidly evolving field of semiconductor nanoelectronics.  In this work, ultrathin fluorescent nanodiamond (FND) films are developed to function as quantum sensors for in operando measurements of magnetic fields and temperature in semiconductor devices.  FNDs are electrically insulating carbon nanomaterials containing nitrogen-vacancy (NV) centers, renowned for their exceptional photostability and distinctive quantum properties.  An electrospray deposition method is first established to produce uniform, near-monolayer FND films on bipolar junction transistors (BJTs) and field-effect transistors (FETs) without compromising their performance.  Then, optically detected magnetic resonance (ODMR)s is employed to detect magnetic fields and monitor temperature increases as electrical currents are passed through the FND-coated semiconductor chips.  Finally, we introduce a technique called FND-based lock-in photoluminescence (PL) thermography, which enables wide-field, real-time temperature sensing and imaging of these actively operating BJTs and FETs with nanometric spatial and millisecond temporal resolution.  In comparison to ODMR, this innovative PL thermography method offers enhanced practicality and ease of implementation, making it well-suited for diagnostic applications in semiconductor devices. 

The interaction between light and molecules under quantum electrodynamics (QED) has long been less emphasized in physical chemistry, as semiclassical theories have dominated due to their relative simplicity. Recent experimental advances in polariton chemistry highlight the need for a theoretical framework that transcends traditional cavity QED and molecular QED models. Macroscopic QED is presented as a unified framework that seamlessly incorporates infinite photonic modes and dielectric environments, enabling applications to systems involving plasmon polaritons and cavity photons. This Perspective demonstrates the applicability of macroscopic QED to chemical phenomena through breakthroughs in molecular fluorescence, resonance energy transfer, and electron transfer. The macroscopic QED framework not only resolves the limitations of classical theories in physical chemistry but also achieves parameter-free predictions of experimental results, bridging quantum optics and material science. By addressing theoretical bottlenecks and unveiling new mechanisms, macroscopic QED establishes itself as an indispensable tool for studying QED effects on chemical systems.

Open quantum systems are susceptible to losses in information, energy, and particles due to their surrounding environment. One novel strategy to mitigate these losses is to transform them into advantages for quantum technologies through tailored non-Hermitian quantum systems. In this work, we theoretically propose a fast generation of multipartite entanglement in non-Hermitian qubits. Our findings reveal that weakly coupled non-Hermitian qubits can accelerate multiparty entanglement generation by thousands of times compared to Hermitian qubits, in particular when approaching the 2^n-th order exceptional points of n qubits in the PT-symmetric regime. Furthermore, we show that Hermitian qubits can generate GHZ states with a high fidelity more than 0.9995 in a timescale comparable to that of non-Hermitian qubits, but at the expense of intense driving and large coupling constant. Our approach is scalable to a large number of qubits, presenting a promising pathway for advancing quantum technologies through the non-Hermiticity and higher-order exceptional points in many-body quantum systems.

The quantum-electrodynamic non-adiabatic emission (QED-NAE) is a type of radiatively assisted vibronic de-excitation due to electromagnetic vacuum fluctuations on non-adiabatic processes. Building on our previous work [Tsai et al., J. Phys. Chem. Lett. 14, 5924 (2023)], we extend the theory of the QED-NAE rate from a single cavity photonic mode to infinite photonic modes and calculate the QED-NAE rates of 9-cyanoanthracene at the first-principles level. To avoid the confusion, the quantum electrodynamic internal conversion process is renamed as “QED-NAE” in our present work. According to our theory, we identify three key factors influencing the QED-NAE processes: light–matter coupling strength (mode volume), mass-weighted orientation factor, and photonic density of states. The mode volume is the primary factor causing rate differences between the two scenarios. In a single cavity with a small mode volume, strong light–matter coupling strength boosts QED-NAE rates. In contrast, in free space with infinite photonic modes, weak coupling strength significantly reduces these rates. From a single cavity photonic mode to infinite photonic modes, the mass-weighted orientation factor only causes an 8π/3-fold increase in the QED-NAE rate. In free space, the photonic density of state exhibits a flat and quadratic distribution, which slightly reduces the QED-NAE rate. Our study shows that cavities can significantly enhance non-adiabatic QED effects while providing a robust analysis demonstrating that QED vibronic effects can be safely ignored in free space.