Hasil untuk "physics.ed-ph"

Bradley A. Webb, Michael S. Chimenti, M. Jacobson et al.

J. Casey, S. Grinstein, J. Orlowski

E. O. Mclean

Gero Miesenböck, D. A. D. Angelis, J. Rothman

Jungmin Lee, R. Durst, R. Wrolstad

A. Gourine, V. Kasymov, N. Marina et al.

M. Friedman, Hella Jürgens

Alejandro R. Urzúa

This work presents a pedagogical and self-contained derivation of the first-order effective Hamiltonian for the two-mode Jaynes-Cummings model in the dispersive regime. A perturbative unitary transformation removes nonresonant atom-field terms, revealing dispersive frequency shifts leading to an atom-induced effective beam-splitter interaction between the field modes. The resulting Hamiltonian is diagonalized through a simple geometric rotation in the two-mode bosonic space, providing a transparent interpretation of the underlying dynamics. The exposition emphasized clarity and physical insight, making effective Hamiltonian methods accessible for teaching and learning in multimode light-matter interactions.

Richard A. Wolf, Pavithran Iyer

With the significance of continuous-variable quantum computing increasing thanks to the achievements of light-based quantum hardware, making it available to learner audiences outside physics has been an important yet seldom-tackled challenge. Similarly, the rising focus on fault-tolerant quantum computing has shed light on quantum error correction schemes, turning it into the locus of attention for industry and academia alike. In this paper, we explore the widely adopted framework of quantum error correction based on continuous variable systems and suggest a guide on building a self-contained learning session targeting the famous Gottesman-Kitaev-Preskill (GKP) code through its geometric intuition.

M. Salazar-Ramírez, D. Ojeda-Guillén, J. A. Martínez-Nuño et al.

In this article we investigate and solve exactly the modified Dirac oscillator in curved spacetime with spin and pseudospin symmetries through an algebraic approach. By focusing on the radial part of this problem, we use the Schrödinger factorization method to show that this problem possesses an SU(1; 1) symmetry. This symmetry allowed us to obtain the wave functions and their corresponding energy spectrum. From these results, we calculate the radial coherent states of the modified Dirac oscillator and their temporal evolution in the spin and pseudospin limits, respectively.

Jingfang Shangguan, Dinggeng He, Xiaoxiao He et al.

Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels.

V. B. Maciel, C. Yoshida, T. Franco

A polyelectrolyte complex (PEC) matrix formed between chitosan and pectin was developed to entrap a bioactive compound (anthocyanin), obtaining an useful pH indicator device. Polysaccharides of opposite charges such as chitosan and pectin can have a very strong intermolecular interaction. The innovation lies in obtaining a new system based on natural and biodegradable compounds, which is simple to manufacture, to indicate variation in pH by visual changes in colour. This device has potential applications in food packaging. The PEC was studied using chitosan and pectin solutions at different pHs values (3.0, 4.0, 5.0 and 5.5) and pectin/chitosan molar ratios (1.0 to 10/1.0 to 5.0). PEC films were homogeneous and showed the highest yield (60.0%) at pH 5.5. Diffusion tests indicated efficient bioactive compound entrapment in the PEC matrix. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy indicate the compatibility between the polymers and bioactive compound.

B. Cerozi, K. Fitzsimmons

Zhiwei Chong

This paper examines the details of an inelastic collision when a bullet shoots a block vertically upward from below. With the assumption of constant interaction force between them, we obtain quantities of interest including the displacement for the block at the end of collision, the collision time, and in particular, the bullet's depth inside the block, which are not studied under the traditional assumption of very short collision time. We identify the condition under which the collision time can indeed be considered as negligibly short. The theory is applied to a well-known demonstration. Using the data extracted from photos of the demonstration, we calculate the magnitude of interaction force and the collision time, which can in no way be easily measured otherwise.

A. Behnood, K. Tittelboom, N. Belie

A. Tamayol, M. Akbari, Y. Zilberman et al.

Yang Zhao, Wei Ren, Ting Zhong et al.

Y. Zou, Zhen Hu, Jian Zhang et al.

Celia Anteneodo, Carolina Brito, Débora P. Menezes

We have carried out a partial survey on the female participation in events organized by the Brazilian Physical Society (SBF, in Portuguese) from 2005 to 2021. Our analysis shows that the participation of women has increased over the years, reaching in some areas, the same percentage as the one observed in the SBF community (always lower that 25\%). However, the participation as members of organizing committees and as keynote speakers is always lower. Some propositions to change this inequality situation are listed.

C. Yoshida, V. B. Maciel, M.E.V. Mendonça et al.