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Tunnels excavated in squeezing ground conditions often experience time-dependent convergence, significantly challenging their stability and demanding robust support systems. Therefore, timely installation of supports is crucial for ensuring safe operations. The Convergence Confinement Method (CCM), which utilizes Longitudinal Deformation Profiles (LDPs), offers a practical tool to determine optimum support system installation points. However, many studies overlook the creep effect when analyzing LDPs and designing a preliminary support. To address this, present study investigates time-dependent LDPs for four tunnel chainages of the Seri Nala region, Atal tunnel, India. A visco-elastic perfectly plastic (VEPP) model was utilized to effectively capture the creep behaviour of the surrounding rock mass. A 2D plane-strain finite element back-analysis was conducted to evaluate the VEPP parameters using a field-instrumented data. Subsequently, these parameters including shear modulus, viscosities, and retardation time; facilitated the construction of LDPs through axisymmetric analyses, revealing the intricate deformation characteristics along the tunnel sections. Moreover, study was further extended to examine the effects of constitutive models, excavation rate and anisotropic stress ratios on LDPs. The findings reveal that different constitutive models produce distinct LDPs, with the Kelvin-Voigt and VEPP models producing significantly higher time-dependent displacements than traditional elastic and elasto-plastic models. This discrepancy underscores the importance of considering viscous and plastic behaviour into deformation analyses. Additionally, the study emphasizes the critical role of excavation rates in managing tunnel stability, as lower rates resulted in increased deformation due to creep effects. The transition from elastic to visco-elastic and visco-elastic perfectly plastic behaviour, influenced by anisotropic stress ratios, further highlights the complexities involved in tunnel design. Overall, this research provides valuable insights for researchers and practitioners, aiding in the safe and cost-effective construction of tunnels. [ABSTRACT FROM AUTHOR]

Non-Hermitian (NH) photonic systems leverage gain and loss to open new directions for nanophotonic technologies. However, the quantum and thermal noise intrinsically associated with gain/loss affects the eigenvalue/eigenvector structure of NH systems, and thus the existence of exceptional points, as well as the practical noise performance of these systems. Here, we present a comparative analysis of the impact of different gain and loss mechanisms on the noise generated in gain–loss compensated NH waveguide systems. Our results highlight important differences in the eigenvalue/eigenvector structure, noise power, photon statistics and squeezing. At the same time, we identify some universal properties such as the occurrence of phase-transition points in parameter space and intriguing phenomena related to them, including coalescence of pairs of eigenvectors, gain–loss compensation, and linear scaling of the noise with the length of the waveguide. We believe that these results contribute to a better understanding of the impact of the gain/loss mechanism on the noise generated in NH systems. [ABSTRACT FROM AUTHOR]

Quantum optical networks are instrumental in addressing the fundamental questions and enable applications ranging from communication to computation and, more recently, machine learning (ML). In particular, photonic artificial neural networks (ANNs) offer the opportunity to exploit the advantages of both classical and quantum optics. Photonic neuro-inspired computation and ML have been successfully demonstrated in classical settings, while quantum optical networks have triggered breakthrough applications such as teleportation, quantum key distribution and quantum computing. We present a perspective on the state of the art in quantum optical ML and the potential advantages of ANNs in circuit designs and beyond, in more general, analogue settings characterized by recurrent and coherent complex interactions. We consider two analogue neuro-inspired applications, namely quantum reservoir computing and quantum associative memories, and discuss the enhanced capabilities offered by quantum substrates, highlighting the specific role of light squeezing in this context. This article is part of the theme issue 'The quantum theory of light'. [ABSTRACT FROM AUTHOR]

We derive a compact expression for the second-order correlation function g(2)(0) of a quantum state in terms of its Wigner function, thereby establishing a direct link between g(2)(0) and the state's shape in phase space. We conduct an experiment that simultaneously measures g(2)(0) through direct photocounting and reconstructs the Wigner function via homodyne tomography. The results confirm our theoretical predictions. This article is part of the theme issue 'The quantum theory of light'. [ABSTRACT FROM AUTHOR]

We construct a class of nonlinear coherent states (NLCSs) by introducing a more general nonlinear function and study their nonclassical properties, specifically the second-order correlation function g (2) (0) , Mandel parameter Q, squeezing, amplitude-squared squeezing and Wigner function of the optical field. The results indicate that the nonclassical properties of the new types of even and odd NLCSs crucially depend on the nonlinear functions. More concretely, we find that the new even NLCSs could exhibit the photon-bunching effect, whereas the new odd NLCSs could show the photon-antibunching effect. The degree of squeezing is also significantly affected by the parameter selection of these NLCSs. By employing various forms of nonlinear functions, it becomes possible to construct the NLCSs with diverse properties, thereby providing a theoretical foundation for the corresponding experimental investigations. [ABSTRACT FROM AUTHOR]

This research investigates the dynamic magnetohydrodynamics flow and radiative heat transfer of Casson Ternary Nanofluid (TN) flowing between two parallel surfaces within a porous medium accompanied by chemical reactions. The TN comprises of Graphene, Graphene Oxide, and Silver dispersed in Sodium Alginate. The governing equations are transformed into dimensionless equations using appropriate similarity variables and solved by Keller-box method. The study discusses the effects of squeeze, magnetic fields, porous medium, chemical reactions, nanoparticles volumetric percentage, and thermal radiation on flow behavior and physical quantities. Comparison of the obtained results with previously published outcomes demonstrates satisfactory agreement, validating the method. The results reveal that squeezing between the parallel surfaces enhances fluid velocity, with a slowdown observed in the center as parameters Hartmann number as well as volume fractions of nanoparticles increase. Convective heat transfer and temperature decrease with rising values of chemical reaction along with volume fractions of nanoparticles. Concentration increases and mass transfer rate decreases with constructive chemical reactions, while opposite trends are observed for destructive chemical reactions.

The deep geological repository for radioactive waste in Switzerland will be embedded in an approximately 100 m thick layer of Opalinus Clay. The emplacement drifts for high-level waste (approximately 3.5 m diameter) are planned to be excavated with a shielded tunnel boring machine (TBM) and supported by a segmental lining. At the repository depth of 900 m in the designated siting region Nördlich Lägern, squeezing conditions may be encountered due to the rock strength and the high hydrostatic pressure (90 bar). This paper presents a detailed assessment of the shield jamming and lining overstressing hazards, considering a stiff lining (resistance principle) and a deformable lining (yielding principle), and proposes conceptual design solutions. The assessment is based on three-dimensional transient hydromechanical simulations, which additionally consider the effects of ground anisotropy and the desaturation that may occur under negative pore pressures generated during the drift excavation. By addressing these design issues, the paper takes the opportunity to analyse some more fundamental aspects related to the influences of anisotropy and desaturation on the development of rock convergences and pressures over time, and their markedly different effects on the two lining systems. The results demonstrate that, regardless of these effects, shield jamming can be avoided with a moderate TBM overcut, however overstressing of a stiff lining may be critical depending on whether the ground desaturates. This uncertainty is eliminated using a deformable system with reasonable dimensions of yielding elements, which can also accommodate thermal strains generated due to the high temperature of the disposal canisters.

We calculate the second-order moments, the Robertson–Schrödinger uncertainty product, and the Mandel factor for various superpositions of coherent phase states with opposite arguments, comparing the results with similar superpositions of the usual (Klauder–Glauber–Sudarshan) coherent states. We discover that the coordinate variance in the analog of even coherent states can show the most strong squeezing effect, close to the maximal possible squeezing for the given mean photon number. On the other hand, the Robertson–Schrödinger (RS) uncertainty product in superpositions of coherent phase states increases much slower (as function of the mean photon number) than in superpositions of the usual coherent states. A nontrivial behavior of the Mandel factor for small mean photon numbers is discovered in superpositions with unequal weights of two components. An exceptional nature of the even and odd superpositions is demonstrated. [ABSTRACT FROM AUTHOR]

The study investigates the application of shotcrete as a temporary support during tunnel excavation, emphasizing its role in stabilizing rock fragments by understanding the load-transfer mechanism. Current research problems include a lack of standardized methodologies for designing primary shotcrete linings and insufficient understanding of shotcrete behavior under varying stress conditions, particularly in squeezing ground conditions. The proposed method utilizes the convergence-confinement method and support capacity plots to design shotcrete linings. This approach is demonstrated through a non-linear, finite element analysis of four tunnel sections of the Atal tunnel, India. Initially, empirical approaches were used to analyze the squeezing effects using geological data, followed by 2D plane strain and axisymmetric analysis to establish ground reaction curves (GRC) and longitudinal deformation profiles (LDP). Subsequently, analytical solutions were used to construct support characteristic curve (SCC), and rock-support interaction curves were generated using these three components (GRC, LDP, and SCC). Further, the study examined the effects of parameters such as age, grade, thickness of the shotcrete, disturbance factor, and anisotropic stress on axial force, bending moment, and shear forces in the shotcrete. Additionally, the shear capacity and bending capacity plots were constructed to evaluate shotcrete stability. Findings indicate that C40 shotcrete with a thickness of 0.35 m provides adequate structural resilience against shearing and bending forces. However, this design is deemed unsafe for both shearing and bending when disturbance factors and anisotropic stress ratios were considered. Specifically, increasing the disturbance factor from 0 to 1 result in a substantial increase in axial force by 64.4%. Under the isotropic stress conditions (ko = 1), shotcrete exhibits uniform axial force distribution; however, when ko = 0.5, axial forces at the springline increase by 6%, and when ko = 1.5, axial forces at the crown and invert increases by 67%. These findings underscore the importance of selecting appropriate shotcrete grade and thickness to ensure the safety and stability of tunnel linings under various stress conditions. This comprehensive analysis offers a novel approach by integrating empirical, analytical, and numerical methods to evaluate shotcrete performance, providing valuable insights for engineers dealing with similar geological conditions. The study offers a realistic and practical method for shotcrete lining design in circular excavations subjected to anisotropic stresses and disturbances in squeezing ground conditions. [ABSTRACT FROM AUTHOR]

We discuss two-photon physics, taking for illustration the particular but topical case of resonance fluorescence. We show that the basic concepts of interferences and correlations provide at the two-photon level an independent and drastically different picture than at the one-photon level, with landscapes of correlations that reveal various processes by spanning over all the possible frequencies at which the system can emit. Such landscapes typically present lines of photon bunching and circles of antibunching. The theoretical edifice to account for these features rests on two pillars: (i) a theory of frequency-resolved photon correlations and (ii) admixing classical and quantum fields. While experimental efforts have been to date concentrated on correlations between spectral peaks, strong correlations exist between photons emitted away from the peaks, which are accessible only through multi-photon observables. These could be exploited for both fundamental understanding of quantum-optical processes as well as applications by harnessing these unsuspected resources. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'. [ABSTRACT FROM AUTHOR]

We study the Hong–Mandel higher-order squeezing of both quadrature components for an arbitrary 2 n th-order (n ≠1) considering the most general Hermitian operator, X θ = X 1 cos θ + iX 2 sin θ , in the superposed state, | Ψ 〉 = K [|Ψ 0) + re i ϕ |0〉] of the orthogonal even coherent state and vacuum state. Here | Ψ 0 〉 = K [|α, +〉 + |iα, +〉] is the orthogonal coherent state, |α, +〉 = K ′[|α) + | – α〉] and | i α, +〉 = K ″ [| i α, +〉 + | – i α, +〉] are even coherent states, operators X 1,2 are defined by X 1 + iX 2 = a, a is the annihilation operator, α, θ , r and ϕ are arbitrary parameters and the only restriction on these is the normalization condition of the superposed state | Ψ 〉. We find that maximum simultaneous 2 n th-order Hong–Mandel squeezing of both quadrature components X θ and X θ+π /2 exhibited by the orthogonal even coherent state enhances in its superposition with vacuum state. We conclude that the values of higher-order momenta in the superposed state become much closer to the best minimum values of the corresponding values of higher-order momenta explored numerically so far than that obtained in orthogonal even coherent state. Variations of 2 n th-order squeezing for n = 2,3 and 4, i.e. fourth, sixth and eighth-order squeezing with different parameters have also been discussed. [ABSTRACT FROM AUTHOR]

Malaria is a potentially fatal plasmodium parasite injected by female anopheles mosquitoes that infect red blood cells and cause millions of lifelong disability worldwide yearly. However, specialists' manual screening in clinical practice is laborious and prone to error. Therefore, a novel Deep Boosted and Ensemble Learning (DBEL) framework, comprising the stacking of new Boosted-BR-STM convolutional neural networks (CNN) and the ensemble ML classifiers, is developed to screen malaria parasite images. The proposed Boosted-BR-STM is based on a new dilated-convolutional block-based Split Transform Merge (STM) and feature-map Squeezing–Boosting (SB) ideas. Moreover, the new STM block uses regional and boundary operations to learn the malaria parasite's homogeneity, heterogeneity, and boundary with patterns. Furthermore, the diverse boosted channels are attained by employing Transfer Learning-based new feature-map SB in STM blocks at the abstract, medium, and conclusion levels to learn minute intensity and texture variation of the parasitic pattern. Additionally, to enhance the learning capacity of Boosted-BR-STM and foster a more diverse representation of features, boosting at the final stage is achieved through TL by utilizing multipath residual learning. The proposed DBEL framework implicates the stacking of prominent and diverse boosted channels and provides the generated discriminative features of the developed Boosted-BR-STM to the ensemble of ML classifiers. The proposed framework improves the discrimination ability and generalization of ensemble learning. Moreover, the deep feature spaces of the developed Boosted-BR-STM and customized CNNs are fed into ML classifiers for comparative analysis. The proposed DBEL framework outperforms the existing techniques on the NIH malaria dataset that are enhanced using discrete wavelet transform to enrich feature space. The proposed DBEL framework achieved Accuracy (98.50%), Sensitivity (0.9920), F-score (0.9850), and AUC (0.9960), which suggests it to be utilized for malaria parasite screening. [ABSTRACT FROM AUTHOR]

Nonlinear optical phenomena have noticeable importance in quantum computation and quantum information processing. The optical nonlinearity leads to the generation of new frequency components possessing nonclassical properties. In this paper, we have investigated nonclassical properties of output beams from a degenerate parametric amplifier (DPA) based on both linear and nonlinear coherent state approaches. Considering the rotating wave approximation, solutions of the Heisenberg equations of motion associated with the standard coherent and nonlinear coherent radiation fields are compared. Nonclassical properties including the first- and second-order squeezing, anti-bunching and photon statistics are investigated for the signal mode starting with different input field states. The calculations based on both approaches confirm the existence of the first-order squeezing in position quadrature ( x ^ 1 (X ^ 1) for linear(nonlinear) approach) of the field with no squeezing in momentum quadrature, while the second-order squeezing occurs in the momentum quadrature of the field ( x ^ 2 (X ^ 2) for linear(nonlinear) approach) with no squeezing in position quadrature. In addition, photon statistics has been studied wherein anti-bunching has been observed using both approaches. The comparison of the obtained results from the two approaches confirms that in the nonlinear approach the nonclassical properties of the output beams are more amplified. [ABSTRACT FROM AUTHOR]

Abstract Malaria is a potentially fatal plasmodium parasite injected by female anopheles mosquitoes that infect red blood cells and cause millions of lifelong disability worldwide yearly. However, specialists’ manual screening in clinical practice is laborious and prone to error. Therefore, a novel Deep Boosted and Ensemble Learning (DBEL) framework, comprising the stacking of new Boosted-BR-STM convolutional neural networks (CNN) and the ensemble ML classifiers, is developed to screen malaria parasite images. The proposed Boosted-BR-STM is based on a new dilated-convolutional block-based Split Transform Merge (STM) and feature-map Squeezing–Boosting (SB) ideas. Moreover, the new STM block uses regional and boundary operations to learn the malaria parasite’s homogeneity, heterogeneity, and boundary with patterns. Furthermore, the diverse boosted channels are attained by employing Transfer Learning-based new feature-map SB in STM blocks at the abstract, medium, and conclusion levels to learn minute intensity and texture variation of the parasitic pattern. Additionally, to enhance the learning capacity of Boosted-BR-STM and foster a more diverse representation of features, boosting at the final stage is achieved through TL by utilizing multipath residual learning. The proposed DBEL framework implicates the stacking of prominent and diverse boosted channels and provides the generated discriminative features of the developed Boosted-BR-STM to the ensemble of ML classifiers. The proposed framework improves the discrimination ability and generalization of ensemble learning. Moreover, the deep feature spaces of the developed Boosted-BR-STM and customized CNNs are fed into ML classifiers for comparative analysis. The proposed DBEL framework outperforms the existing techniques on the NIH malaria dataset that are enhanced using discrete wavelet transform to enrich feature space. The proposed DBEL framework achieved Accuracy (98.50%), Sensitivity (0.9920), F-score (0.9850), and AUC (0.9960), which suggests it to be utilized for malaria parasite screening.

In this study, we have analyzed fluid mobility and thermal transport of the SiO2/kerosene nanofluid within two rotating stretchable disks. The top disk is simulated to be oscillating with a periodic velocity and squeezing continuously the nanofluid within a porous medium and making the fluid to flow perpendicularly to the situated magnetic field. Thermal radiation effects are considered in the heat transfer model. The non-linear (NL) PDEs that describe the nanofluid mobility structure and thermal transport are transformed into system of NL-ODEs by introducing adequately suitable non-dimensional variables after which the NL-ODEs were numerically solved via spectral quasi-linearization method (SQLM) on overlapping grids. The consequences of several pertinent parameters of the model on pressure, temperature, velocity, skin drag coefficient and thermal transport rate are examined and elucidated in detail with the aid of figures and tables. It was found that the flow structure with prescribing conditions develops negative pressure situation which has vast applications in modern day medical engineering, especially in the construction of air pressure stabilizers used in medical isolation and wound therapy physiology.

Four-wave mixing process (FWM) in the non-degenerate category can be produced by the interaction of the radiation field with the third-order nonlinear optical media. In our present paper, to describe the non-degenerate four-wave mixing process we have used the fully quantum mechanical bosonic Hamiltonian. Heisenberg’s equations of motion for various modes involving pump, signal and idler are constructed. The corresponding differential equations are coupled and nonlinear. Due to non-linearity, the solution of these equations in closed set analytical form is not possible. To solve these coupled nonlinear differential equations we use the Sen-Mandal perturbative technique. Interestingly, this approach provides a broader and more general set of solutions that may be applicable across a wider range of conditions. The Sen-Mandal perturbative technique allows a more general solution that can result in a more accurate and general representation of the system that is more advantageous than the well-known short-time approximation method. The obtained solutions have been used to study the intermodal entanglement, normal order anti-bunching and normal order squeezing for various modes under the non-degenerate four-wave mixing process. The non-degenerate FWM is one of the processes for generating entanglement, squeezing and anti-bunching etc. [ABSTRACT FROM AUTHOR]

In this paper, we study the one-parameter κ -generalized oscillator algebra κ (which includes the case of the standard Weyl–Heisenberg algebra). This algebra admits representations of finite-dimensional for negative values of the parameter κ. We construct the associated Perelomov like coherent states. We discuss their statistical properties. In particular, we derive the expressions of the Mandel parameter and Husimi function and we discuss the squeezing of the κ coherent states. [ABSTRACT FROM AUTHOR]

An efficient random variable generator for a truncated gamma distribution with shape parameter greater than 1 is designed using an acceptance-rejection algorithm. Based on an approximation to a transformed gamma density function by the standard normal density, numerical information for the standard normal density is prepared in advance, and the calculation is performed with reference to that information. An improvement via a squeezing method is proposed to reduce the computational burden and time. The algorithm's acceptance rate for generating truncated gamma variables is very high and almost 1 when the truncated distribution is unimodal. Numerical experiments for one- and two-sided truncated domain cases are conducted to measure the execution time, including the parameter setup time. Compared with existing truncated gamma variate generators, the proposed method performs better when the distribution is unimodal and the shape parameter is equal to or greater than 3.3. [ABSTRACT FROM AUTHOR]

Background: There is no clear objective indicator for selecting soft foods that are required for food bolus formation in older people with impaired oral function. Objective: This study aimed to investigate the relationship between maximal isometric tongue pressure (MITP) and the mechanical properties of gels that can be crushed by the tongue. Methods: This study included 65 healthy participants aged 22–96 (young group; 15 males, 15 females; older dentate group; 7 males, 8 females; older edentulous group; 10 males, 10 females). MITP was measured by the balloon‐probe device. Agar gel with 10 different kinds of fracture force from 10N to 100N was used. The limit of fracture force of gels (LFFG) that were crushed by the tongue was measured by the up‐and‐down method. In the older edentulous group, two items were measured with and without dentures. Spearman's rank correlation coefficient was used to evaluate the relationship between MITP and LFFG in each group (p <.05). Results: There were positive correlations between MITP and LFFG in all groups (overall groups: rs =.66, young group: rs =.46, older dentate group: rs =.61, older edentulous group with dentures: rs =.60, older edentulous group without dentures: rs =.47). Conclusion: MITP and LFFG were positively correlated in young, older dentate and older edentulous groups, suggesting that MITP has the potential to be an objective indicator of the range of mechanical properties of soft food that can be crushed by the tongue. [ABSTRACT FROM AUTHOR]

We introduce this work by studying the non-Newtonian fluids, which have huge applications in different science fields. We decided to concentrate on taking the time-dependent Casson fluid, which is non-Newtonian, compressed between two flat plates. in fractional form and the magnetohydrodynamic and Darcian flow effects in consideration using the semi-analytical iterative method created by Temimi and Ansari, known as TAM, this method is carefully selected to be suitable for studying the Navier-Stokes model in the modified form to express the studied case mathematically. To simplify the partial differential equations of the system to the nonlinear ordinary differential equation of order four the similarity transformations suggested by Wang (1976) are used. The TAM approach demonstrates a high degree of accuracy, efficiency, and convergence when applied to the resolution of both linear and nonlinear problems, and the results in this article are used to study the effect of the related factors like squeeze number Sq, Casson parameterβ, magnetohydrodynamic parameter Mg and permeability constant Mp and examining the skin friction coefficient effect. The velocity profile is studied numerically, which is tabulated and graphically represented to show and confirm the theoretical study. We can conclude that the success of the proposed method in studying time-dependent Casson fluid, which is non-Newtonian, compressed between two flat plates provides opportunities for additional study and advancements in fluid mechanics using the techniques.

The 57-km long, new Gotthard Base Tunnel (GBT) crosses over a 1.1-km long stretch containing kakirites, i.e. weak rocks which, depending on the degree of tectonisation, may exhibit severe squeezing behaviour upon tunnel excavation. This tunnel stretch was already identified as a key problem in the early planning phase, necessitating intensive geological exploration and laboratory investigations over a 14-year period, including research and development in experimental techniques. The laboratory investigations for the GBT provided not only a considerable amount of data about the geotechnical parameters of the kakirites, but also valuable information about their basic behaviour and the adequacy of various testing techniques for this type of rock. Specifically, by using specially designed testing equipment and procedures, it was shown that, (1) conventional rock mechanics triaxial tests cannot provide reliable results for kakirites; (2) the kakirites obey the principle of effective stress in Terzaghi's classical form and consequently it is indispensable to measure the pore pressure during triaxial testing, analogously to the consolidated drained (CD) and consolidated undrained (CU) tests in soil mechanics; (3) the effects of a possible loss of water and desaturation during sampling, transport, storage and preparation of specimens can be successfully mitigated by subjecting the specimens to flow-through before the actual triaxial testing; and, (4) CD tests on partially saturated specimens that are obtained by means of flow-through can provide reliable and reproducible results. This saves a significant amount of time, allows a greater number of tests to be performed, and allows results to be obtained more quickly, which is particularly important for decision-making during tunnel advance.

We analyze the mean intensity and quadrature squeezing of the cavity photons obtained from a three-level laser with input coherent and squeezed fields employing the solution of the quantum Langevin equation. Despite the fact that the input coherent field has a substantial effect on the mean intensity, it does not affect the squeezing of the cavity photons. On the other hand, the input squeezed field improves the mean intensity and the amount of squeezing of the cavity photons. Moreover, the initial mean cavity photons enhance the mean intensity and lower the amount of squeezing of the cavity photons. [ABSTRACT FROM AUTHOR]

One of the most substantial issues faced during the excavation of deep tunnels in weak geomechanical conditions is the squeezing phenomenon. Thrust force determination of the shielded tunnel boring machines (TBMs) in such conditions is of utmost importance. In this study, the Beheshtabad water conveyance tunnel in the central part of Iran is chosen as a case study. The creep parameters of Burger's model (CVISC) are determined using laboratory creep tests on samples from the 19th zone of the tunnel with high squeezing potential, and the results were verified using finite difference simulation of the test. A new approach based on the convergence-confinement method is used to calculate the required thrust force of a double-shield TBM using radial displacement profile (RDP) and ground reaction curve (GRC). The effect of various penetration rates on thrust reduction as well as the impact of different over-boring values and standstill times has been evaluated. The results show that in small values of over-boring, due to high overburden pressure and weak geomechanical conditions, required thrust values are incredibly high and the increment of penetration rate is almost ineffective, and the negative effect of standstill time is more evident. Higher penetration rates have a significant impact on thrust reduction in all cases which is a noticeable factor to avoid TBM jamming under squeezing conditions. In higher over-boring values, thrust reduction is positively conducted through increasing the penetration rate and the negative effect of standstill time is minor. [ABSTRACT FROM AUTHOR]

Squeezing is a well-known geotechnical phenomenon in the excavation of underground spaces, especially tunnels. Squeezing occurs under different geotechnical conditions in weak rock masses. A study was carried out to develop a mathematical and practical model to predict squeezing so that risk mitigation measures can be taken if necessary. A mathematical model based on a gene expression programming algorithm was developed using a database of 115 squeezing case histories. Four model performance evaluation criteria – specificity, sensitivity, accuracy and Matthew's correlation coefficient – and the receiver operating characteristic curve were then assessed based on a testing dataset. The accuracy of the model was also compared with that of previously developed models. Found to be able to determine squeezing with acceptable accuracy, the model was then used to investigate squeezing-prone areas in the Beheshtabad water-conveyance tunnel in Iran. [ABSTRACT FROM AUTHOR]

We introduce this work by studying the non-Newtonian fluids, which have huge applications in different science fields. We decided to concentrate on taking the time-dependent Casson fluid, which is non-Newtonian, compressed between two flat plates. in fractional form and the magnetohydrodynamic and Darcian flow effects in consideration using the semi-analytical iterative method created by Temimi and Ansari, known as TAM, this method is carefully selected to be suitable for studying the Navier-Stokes model in the modified form to express the studied case mathematically. To simplify the partial differential equations of the system to the nonlinear ordinary differential equation of order four the similarity transformations suggested by Wang (1976) are used. The TAM approach demonstrates a high degree of accuracy, efficiency, and convergence when applied to the resolution of both linear and nonlinear problems, and the results in this article are used to study the effect of the related factors like squeeze number Sq, Casson parameterβ, magnetohydrodynamic parameter Mg and permeability constant Mp and examining the skin friction coefficient effect. The velocity profile is studied numerically, which is tabulated and graphically represented to show and confirm the theoretical study. We can conclude that the success of the proposed method in studying time-dependent Casson fluid, which is non-Newtonian, compressed between two flat plates provides opportunities for additional study and advancements in fluid mechanics using the techniques. [ABSTRACT FROM AUTHOR]

Quantum squeezing, an intriguing phenomenon that amplifies the uncertainty of one variable while diminishing that of its conjugate, may be studied as a time-dependent process, with exact solutions frequently derived from frameworks grounded in adiabatic invariants. Remarkably, we reveal that exact solutions can be ascertained in the presence of time-variant elastic forces, eschewing dependence on invariants or frozen eigenstate formalism. Delving into these solutions as an inverse problem unveils their direct connection to the design of elastic fields, responsible for inducing squeezing transformations onto canonical variables. Of particular note is that the dynamic transformations under investigation belong to a class of gentle quantum operations, distinguished by their delicate manipulation of particles, thereby circumventing the abrupt energy surges commonplace in conventional control protocols.

We present the squeezing and entanglement features of the vibrational phonon modes in a double-cavity optomechanical system with input squeezed light. The non-classical features of the vibrational phonon modes arise from the transfer of quantum coherence from the optical to the phonon modes. The phonon modes exhibit squeezing, and the degree of squeezing increases with the increase in the input squeezed light. To quantify the entanglement between the phonon modes, we apply the Hillery and Zubairy criterion. We demonstrate that the entanglement between the phonon modes increases with an increase in optomechanical cooperativity. Moreover, the input squeezed light has a substantial effect on the degree entanglement between the phonon modes.

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This paper for the first time, to the best of our knowledge, reports 10 case histories of jack-up rig installation in different locations of the Gulf of Mexico consisting of seabed soil stratigraphy with weak surface (soft) clay over strong (stiff) clay or sand underlying layers. For each case, site investigation data are analyzed, leading to the selection of design undrained shear strength profile for the clay layers and relative density for the sand layers. A statistical averaging method recommended in the InSafeJIP guidelines (adopted in ISO 19905-1) is used to obtain the best fit of the undrained shear strength profile in the clay layers. The spudcan shape and dimensions and load-penetration profiles are presented. Measured load-penetration profiles are compared with the calculated profiles using the squeezing methods presented in ISO 19905-1, Clarom, and recently published papers. Large deformation finite element analyses were conducted for some sites to provide supporting insight into the penetration resistance profiles and potentially mobilized squeezing mechanisms. The lessons learned are noted, which will provide valuable insights for practitioners for estimating the behavior of jack-up installations in seabed soil consisting of surface weak-over-underlying strong soil stratigraphy. [ABSTRACT FROM AUTHOR]

Schrödinger cat states, consisting of superpositions of macroscopically distinct states, provide key resources for a large number of emerging quantum technologies in quantum information processing. Here we propose how to generate and manipulate mechanical and optical Schrödinger cat states with distinguishable superposition components by exploiting the unique properties of cavity optomechanical systems based on Bose-Einstein condensate. Specifically, we show that in comparison with its solid-state counterparts, almost a 3 order of magnitude enhancement in the size of the mechanical Schrödinger cat state could be achieved, characterizing a much smaller overlap between its two superposed coherent-state components. By exploiting this generated cat state, we further show how to engineer the quadrature squeezing of the mechanical mode. Besides, we also provide an efficient method to create multicomponent optical Schrödinger cat states in our proposed scheme. Our work opens up a new way to achieve nonclassical states of massive objects, facilitating the development of fault-tolerant quantum processors and sensors.

Tunnels in unfavorable ground conditions are exposed to high internal stresses due to localized loading at the outer face. Addition of extra layers of compressible material as a countermeasure needs more material and greater excavation volumes which is in conflict to the global goals of CO2 reduction. Thus, two alternative types of segments with higher bearing capacities are proposed that allow for lining thickness reduction. They are derived from multi‐load topology optimization considering relevant load cases during construction and in service. The first design incorporates centered recesses that maximize segmental stiffness. The second shifts the recesses to the outer face increasing their potential to absorb deformation. Two prototypes of each type are fabricated from high performance steel fiber reinforced concrete. Experiments show that a concrete reduction of up to 55.2% is achieved with respect to a conventional design. The volume savings give space for layers of radially compressible material. [ABSTRACT FROM AUTHOR]

The main results of this paper concern growth in sums of a k-convex function f. Firstly, we streamline the proof (from Hanson et al. (Combinatorica 42:71–85, 2020)) of a growth result for f(A) where A has small additive doubling, and improve the bound by removing logarithmic factors. The result yields an optimal bound for | 2 k f (A) - (2 k - 1) f (A) |. We also generalise a recent result from Hanson et al. (J Lond Math Soc, 2021), proving that for any finite A ⊂ R | 2 k f (s A - s A) - (2 k - 1) f (s A - s A) | ≫ s | A | 2 s where s = k + 1 2 . This allows us to prove that, given any natural number s ∈ N , there exists m = m (s) such that if A ⊂ R , then 1 | (s A - s A) (m) | ≫ s | A | s. This is progress towards a conjecture (Balog et al. in Electron J Comb 24(3):Paper No. 3.14, 17, 2017) which states that (1) can be replaced with | (A - A) (m) | ≫ s | A | s. Developing methods of Solymosi, and Bloom and Jones, and using an idea from Bradshaw et al. (Electron J Comb 29, 2021), we present some new sum-product type results in the complex numbers C and in the function field F q ((t - 1)) . [ABSTRACT FROM AUTHOR]

We present a systematic study on the effects of dynamical transfer and steady-state synchronization of quantum states in a hybrid optomechanical network consisting of two cavities, which carry atoms inside and interact via a common moving mirror such as the mechanical oscillator. It is found that a high fidelity transfer of Schrödinger's cat and squeezed states between two cavities modes is possible. On the other hand, we demonstrate the synchronization effect of the cavity modes in a steady squeezed state with its high fidelity realized by the mechanical oscillator that intermediates the generation, transfer and stabilization of the squeezing. In this framework, we also study the generation and evolution of bipartite and tripartite entanglement and find its connection to the effects of quantum state transfer and synchronization. Particularly, when the transfer occurs at the maximal fidelity, any entanglement is almost zero, so the different cavity modes are disentangled. However, these modes become entangled when the two bosonic modes are synchronized in a stationary squeezed state. The results provided by the current study may find applications in quantum information technologies, in addition to the setups for metrology, where squeezed states are essential. [ABSTRACT FROM AUTHOR]

The atomic squeezing in a system of M two level atoms interacting with a coherent radiation of single mode is analyzed. The time dependent squeezing factor S has been calculated and the impact of the photons number and other parameters are studied. I considered approximation that mean numbers of photons are small in comparison to number of atoms. Small atomic squeezing is obtained under the approximation. One may obtain larger squeezing by increasing the mean number of photons. I plotted the graph for time evaluation of squeezing factor for different value of photons and fixed value of atoms presented in different atomic states. [ABSTRACT FROM AUTHOR]

Multimode properties, based on nonlinear parametric processes, have potential research value on entanglement imaging. This paper studies the spatial and frequency multimode from dressing parametric‐amplified six‐wave mixing (PA‐SWM) process with three entangled signals. The S1 signal contains fifth‐order nonlinearity, the S2 signal contains electromagnetically induced absorption and fifth‐order nonlinearity, and the S3 signal contains Autler–Townes splitting (AT), second‐ and fifth‐order nonlinearity. The frequency multimode is attributed to dressing energy level splitting in spontaneous SWM (SSWM) process. The spatial multimode is due to frequency multimode and beam splitting via Kerr nonlinearity. In the spatial domain, it finds the optimal conditions of intensity difference squeezing (IDS) and spatial imaging along with their competitive relationship. On the one hand, the light spots with single spatial mode are contributed to the maximum IDS but not conducive to entanglement imaging; on the other hand, the light spots with multiple spatial modes are instrumental in entanglement imaging but not appropriate for the IDS. This research has potential applications in squeezed light sources for quantum metrology, and correlated imaging of spatial signals. [ABSTRACT FROM AUTHOR]

Exploring quantum physics in mancroscopic systems and manupulating these systems for various technological applications has been a topic of intense research in the last one decade or so. In this regard, the field of cavity quantum optomechanics turns out to be one of the most rapidly emerging area of research. It has opened many doors to study various open ended fundamental questions in quantum physics, apart from numerous possible applications. A typical cavity optomechanical system consists of two mirrors, one fixed while the other one is movable. These systems may be of micrometer or nano-meter in dimensions. The electromagnetic radiation incident on the system may get coupled to the mechanical motion of the movable mirror. This opto-mechanical coupling is the root of all phenomena such as quantum entanglement, state-transfer, squeezing and so on. In this short tutorial, basic concepts of cavity quantum optomechanics are discussed. We hope that this tutorial would motivate readers, both theorists and experimentalists, to take up advanced studies in this immensely fruitful area of research. [ABSTRACT FROM AUTHOR]

We consider a quantum well with one exciton in a microcavity that initially contains photons and is coupled to a one-mode squeezed vacuum reservoir. The solution of the quantum Langevin equation is used to investigate the intensity, second-order correlation function, intensity spectrum, and quadrature squeezing of the exciton mode in the low-excitation regime. Although the initial cavity photons increase the intensity of the exciton mode, they have an adverse effect on the quadrature squeezing. We also demonstrate that the exciton mode exhibits quadrature squeezing, with the amount of squeezing increased by the input squeezed light. [ABSTRACT FROM AUTHOR]

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Quantum squeezing, an intriguing phenomenon that amplifies the uncertainty of one variable while diminishing that of its conjugate, may be studied as a time-dependent process, with exact solutions frequently derived from frameworks grounded in adiabatic invariants. Remarkably, we reveal that exact solutions can be ascertained in the presence of time-variant elastic forces, eschewing dependence on invariants or frozen eigenstate formalism. Delving into these solutions as an inverse problem unveils their direct connection to the design of elastic fields, responsible for inducing squeezing transformations onto canonical variables. Of particular note is that the dynamic transformations under investigation belong to a class of gentle quantum operations, distinguished by their delicate manipulation of particles, thereby circumventing the abrupt energy surges commonplace in conventional control protocols. [ABSTRACT FROM AUTHOR]

In this paper, we numerically study the coordinate wave functions and the Wigner functions of the coherent phase states (CPS), paying particular attention to their differences from the standard (Klauder–Glauber–Sudarshan) coherent states, especially in the case of the high mean values of the number operator. In this case, the CPS can possess a strong coordinate (or momentum) squeezing, which is roughly twice weaker than for the vacuum squeezed states. The Robertson–Schrödinger invariant uncertainty product in the CPS logarithmically increases with the mean value of the number operator (whereas it is constant for the standard coherent states). Some measures of the (non)Gaussianity of CPS are considered.