arXiv subjects

Yuri Rostovtsev

Publications and source records attributed to Yuri Rostovtsev.

11 recordsLinked to original sources

arXiv2026

Is Parity Violation a Dynamical Effect?

As has been shown by multiple authors in recent decades, it is possible to reformulate various portions of the standard model over the ring of complex quaternions. In this paper, we utilize a complex quaternion spin representation of the spacetime algebra to derive the magnetic moments of standard model fermions and the $W^\pm$ boson. The moments calculated are not limited to those with the photon. We account for coupling to the magnetic fields of each standard model gauge boson. We naively assume that fermions coupled to weak isospin have magnetic moments with the charged bosons. Upon assuming these charged moments exist, we realize that they are to be influenced by the neutral, pseudovector-valued magnetic fields that are observed when a charged particle is moving. Visualizing the derived moments of fermions and charged bosons together, we find a possible explanation for the parity asymmetry observed in charged weak interactions.

hep-ph↗

arXiv2026

Complex Quaternionic Formulations of Dirac, Electrodynamic, and Electroweak Fields and Interactions

A simple translation between a standard representation of $\mathfrak{sl}_2\mathbb{C}$ and the complex-quaternions ($\mathbb{H}\otimes_\mathbb{R}\mathbb{C}$) is established and exploited to construct a novel hyper-complex description of the Dirac theory, electrodynamics, and ultimately the electroweak sector of the standard model. We find that coupling the constructed Dirac spinors to electromagnetism yields the correct magnetic moment for charged spin-1/2 particles. Extending electrodynamics to electroweak theory necessitates an algebraic distinction between the structures of the leptonic and Higgs fields not present in the standard model. The conditions of spontaneous symmetry breaking are explored using an alternative representation of weak isospin and hypercharge equivalent to an irreducible representation of $\mathfrak{su}(2)\oplus\mathfrak{u}(1)$ on $\mathbb{C}^4$. This alternative representation disagrees with the standard model on the overall signs of weak neutral currents.

quant-ph↗

arXiv2019

Ultrafast dephasing in hydrogen-bonded pyridine-water mixtures

Hydrogen-bonded mixtures with varying concentration are a complicated networked system that demands a detection technique with both time and frequency resolutions. Hydrogen-bonded pyridine-water mixtures are studied by a time-frequency resolved coherent Raman spectroscopic technique. Femtosecond broadband dual-pulse excitation and delayed picosecond probing provide sub-picosecond time resolution in the mixtures temporal evolution. For different pyridine concentrations in water, asymmetric blue versus red shifts (relative to pure pyridine spectral peaks) were observed by simultaneously recording both the coherent anti-Stokes and Stokes Raman spectra. Macroscopic coherence dephasing times for the perturbed pyridine ring modes were observed in ranges of 0.9 - 2.6 picoseconds for both 18 and 10 cm-1 broad probe pulses. For high pyridine concentrations in water, an additional spectral broadening (or escalated dephasing) for a triangular ring vibrational mode was observed. This can be understood as a result of ultrafast collective emissions from coherently excited ensemble of pairs of pyridine molecules bound to water molecules.

physics.chem-ph↗

arXiv2019

Active control of coherent dynamics in hybrid plasmonic MoS2 monolayers with dressed phonons

The near-field interaction due to a strong electromagnetic field induced by resonant localized plasmons can result in a strong coupling of excitonic states or formation of hybrid exciton-plasmon modes in quantum confined structures. This coupling can be strengthed by designing a system with its vibronic states resonant to the energy of the driving field induced by the localized plasmon excitation. Silver nanoislands nucleated on molybdenum disulfide (MoS2) is an ideal platform for such interaction. The influence of localized plasmons (LSP) on the formation and dissociation of excitons due to resonant and off-resonant optical excitation of carriers to excitonic states is studied using ultrafast optical spectroscopy. The local field due to the Ag nanoparticles (Ag-NP) enhances the magnitude of the Raman modes in MoS2 in the presence of resonant excitation. An ultrashort pulsed optical excitation at 2.3 eV resonantly excites the LSP modes and the optical near-field resonantly drive the phonon modes, which leads to a coherent coupling of the A and B excitons in MoS2 with the plasmon modes. The resonant excitation of the LSP modes modulate the optical absorption of the probe field. The resonant excitation of C exciton due to an excitation source at 3.0 eV, which is off-resonant to the LSP mode increases the electrostatic screening in the presence of excess carriers from Ag NPs. It results in a faster dissociation of optically generated C excitons into free carriers that eventually increase the A and B exciton population. A 3-level density matrix theory in the presence of dressed vibronic states induced by a localized near-field optical driving source is applied to describe the coherent interaction process in the hybrid nano-plasmonic system.

cond-mat.mes-hall↗

arXiv2018

Improvement of photovoltaic efficiency by Fano coherence

We show that Fano resonance in the decay channels of a three-level system can lead to considerably absorption enhancement and emission suppression. We found that a coherence built up in the ground doublet states, with strength depending on a coupling parameter that arises from the Fano interference, can in principle lead to breaking of the detail balance between the absorption and emission processes in atomic systems.

physics.optics↗

arXiv2018

Analytic solution and pulse area theorem for three-level atoms

We report an analytic solution for a three-level atom driven by arbitrary time-dependent electromagnetic pulses. In particular, we consider far-detuned driving pulses and show an excellent match between our analytic result and the numerical simulations. We use our solution to derive a pulse area theorem for three--level $V$ and $Λ$ systems without making the rotating wave approximation. Formulated as an energy conservation law, this pulse area theorem provides a simple picture for a pulse propagation through a three--level media.

quant-ph↗

arXiv2018

Magnus expansion method for two-level atom interacting with few-cycle pulse

Using the Magnus expansion to the fourth order, we obtain analytic expressions for the atomic state of a two-level system driven by a laser pulse of arbitrary shape with small pulse area. We also determine the limitation of our obtained formulas due to limited range of convergence of the Magnus series. We compare our method to the recently developed method of Rostovtsev et al. (PRA 2009, 79, 063833) for several detunings. Our analysis shows that our technique based on the Magnus expansion can be used as a complementary method to the one in PRA 2009.

quant-ph↗

arXiv2006

Generation of coherent terahertz pulses in Ruby at room temperature

We have shown that a coherently driven solid state medium can potentially produce strong controllable short pulses of THz radiation. The high efficiency of the technique is based on excitation of maximal THz coherence by applying resonant optical pulses to the medium. The excited coherence in the medium is connected to macroscopic polarization coupled to THz radiation. We have performed detailed simulations by solving the coupled density matrix and Maxwell equations. By using a simple $V$-type energy scheme for ruby, we have demonstrated that the energy of generated THz pulses ranges from hundreds of pico-Joules to nano-Joules at room temperature and micro-Joules at liquid helium temperature, with pulse durations from picoseconds to tens of nanoseconds. We have also suggested a coherent ruby source that lases on two optical wavelengths and simultaneously generates THz radiation. We discussed also possibilities of extension of the technique to different solid-state materials.

quant-ph↗

arXiv2002

From Laser Induced Line Narrowing To Electromagnetically Induced Transparency: Closed System Analysis

Laser induced line narrowing effect, discovered more than thirty years ago, can also be applied to recent studies in high resolution spectroscopy based on electromagnetically induced transparency. In this paper we first present a general form of the transmission width of electromagnetically induced transparency in a homogeneously broadened medium. We then analyze a Doppler broadened medium by using a Lorentzian function as the atomic velocity distribution. The dependence of the transmission linewidth on the driving field intensity is discussed and compared to the laser induced line narrowing effect. This dependence can be characterized by a parameter which can be regarded as ``the degree of optical pumping''.

physics.atom-ph↗

arXiv2000

Freezing Light via hot gases

We prove that it is possible to freeze a light pulse (i.e., to bring it to a full stop) or even to make its group velocity negative in a coherently driven Doppler broadened atomic medium via electromagnetically induced transparency (EIT). This remarkable phenomenon of the ultra-slow EIT polariton is based on the spatial dispersion of the refraction index $n(\w,k)$, i.e., its wavenumber dependence, which is due to atomic motion and provides a negative contribution to the group velocity. This is related to, but qualitatively different from, the recently observed light slowing caused by large temporal (frequency) dispersion.

quant-ph↗

arXiv1999

Ultra-Slow Light and Enhanced Nonlinear Optical Effects in a Coherently Driven Hot Atomic Gas

We report the observation of small group velocities of order 90 meters per second, and large group delays of greater than 0.26 ms, in an optically dense hot rubidium gas (~360 K). Media of this kind yield strong nonlinear interactions between very weak optical fields, and very sharp spectral features. The result is in agreement with previous studies on nonlinear spectroscopy of dense coherent media.

quant-ph↗