Correlations and commuting transfer matrices in integrable unitary circuits

We consider a unitary circuit where the underlying gates are chosen to be \check{R}Ř-matrices satisfying the Yang-Baxter equation and correlation functions can be expressed through a transfer matrix formalism. These transfer matrices are no longer Hermitian and differ from the ones guaranteeing local conservation laws, but remain mutually commuting at different values of the spectral parameter defining the circuit. Exact eigenstates can still be constructed as a Bethe ansatz, but while these transfer matrices are diagonalizable in the inhomogeneous case, the homogeneous limit corresponds to an exceptional point where multiple eigenstates coalesce and Jordan blocks appear. Remarkably, the complete set of (generalized) eigenstates is only obtained when taking into account a combinatorial number of nontrivial vacuum states. In all cases, the Bethe equations reduce to those of the integrable spin-1 chain and exhibit a global SU(2) symmetry, significantly reducing the total number of eigenstates required in the calculation of correlation functions. A similar construction is shown to hold for the calculation of out-of-time-order correlations.

Chiral light in single-handed Fabry-Perot resonators

Chirality is a universal phenomenon that is encountered on many different length scales in nature. Interaction of chiral matter with chiral light results in the effect of circular dichroism, which underlies many techniques of discriminating molecular enantiomers. Enhancing dichroic effects is typically achieved by interfacing chiral matter with various optical resonators. In this context it is important to understand how the eigenmodes of optical cavities relate to the field states with well-defined handedness. Here, we present the model of a single-handedness chiral optical cavity supporting only an eigenmode of a given handedness without the presence of modes of other helicity. Resonant excitation of the cavity with light of appropriate handedness enables formation of a helical standing wave with a uniform chirality density, while the opposite handedness does not cause any resonant effects. Our findings expand the set of tools for investigations of chiral matter and open the door towards studies of chiral electromagnetic vacuum states.

Non-Oscillatory Power Spectrum From States of Low Energy in Kinetically Dominated Early Universes

Recently, States of Low Energy (SLEs) have been proposed as viable vacuum states of primordial perturbations within Loop Quantum Cosmology (LQC). In this work we investigate the effect of the high curvature region of LQC on the definition of SLEs. Shifting the support of the test function that defines them away from this regime results in primordial power spectra of perturbations closer to those of the so-called Non-oscillatory (NO) vacuum, which is another viable choice of initial conditions previously introduced in the LQC context. Furthermore, through a comparison with the Hadamard-like SLEs, we prove that the NO vacuum is of Hadamard type as well.

Entanglement of a System of an Indirectly Linked Two-Coupled-Cavity through an Optical Fiber Cable for Single Excitation Atomic States in the Presence of an External Field

The dynamics of the quantum entropies of a system of two cavities coupled by an optical fiber cable, each cavity contains a two-level atom interacting with a single electromagnetic field in addition to an external classical field, is investigated. Under canonical transformations, the considered Hamiltonian is diagonalized. Effective Hamiltonians in three different limiting regimes: namely large optical fiber cable coupling bstrength, large detunig, and comparable detuning and optical fiber cable coupling strength, are derived. The ith ¯ -tom are respectively prepared in the superposition coherent and the ground states while the fields are prepared in the vacuum states. An analytical expression for the solution of the Schr¨odinger equation for each dispersive is derived. The degree of entanglement (DEM) is studied by using von Neumann atomic entropies. The influences of both the optical fiber cable coupling strength and the detuning on the evolution of the DEM ”their values are closely chosen to be compatible with the imposed restrictions for the applications of the different regimes” are analyzed. General conclusions reached are illustrated by numerical results.

Experiment Regarding Magnetic Fields with Gravity

The ground-based device simulates the potential energy (voltages) between gravity and magnetic seas. The magnetic sea generator (MG) generated currents and voltages on the mesoscopic scale in the vacuum. Gravity interacts to generate electricity in the Earth's direction or the opposite direction by the repulsive magnetic force. A trapped gravity was set to behave as free relativistic quantum particles or fluids, making it possible to measure the voltage and current as a function of time according to the particle or fluid interaction and position in the magnetic sea. Our result is grounded on rigorous proof based on numerical and analytic computations, which took it accessible to study the magnetic sea for different initial superposition of positive- negative-gravity spinor state in the space Hieut (H). As evidence, we present the measurement data of gravitational waves (GW20200618), which were impossible to measure during the pandemic at LIGO. If the MG generates negative current and positive voltage in vacuum states, this signifies the gravitomagnetic potentials induced by gravitational fluids or particles in the magnetic sea. The theory of quantum mechanics can be merged with the theory of general relativity or gravitational force at microscopic length scales. Now, we can convert the study of light trapped in a black hole into a study of gravity trapped in space H.

Entanglement-assisted capacity regions and protocol designs for quantum multiple-access channels

We solve the entanglement-assisted (EA) classical capacity region of quantum multiple-access channels (MACs) with an arbitrary number of senders. As an example, we consider the bosonic thermal-loss MAC and solve the one-shot capacity region enabled by an entanglement source composed of sender-receiver pairwise two-mode squeezed vacuum states. The EA capacity region is strictly larger than the capacity region without entanglement-assistance. With two-mode squeezed vacuum states as the source and phase modulation as the encoding, we also design practical receiver protocols to realize the entanglement advantages. Four practical receiver designs, based on optical parametric amplifiers, are given and analyzed. In the parameter region of a large noise background, the receivers can enable a simultaneous rate advantage of 82.0% for each sender. Due to teleportation and superdense coding, our results for EA classical communication can be directly extended to EA quantum communication at half of the rates. Our work provides a unique and practical network communication scenario where entanglement can be beneficial.