International Journal of Theoretical Physics最新文献

Teleportation across short distances has become relevant in view of some recent developments in quantum technology. The advantage here is that certain auxiliary qubits can be accessed and utilized by both the sender and the receiver. Such an act reduces the requirement of the number of qubits in the entangled quantum channel which would have been otherwise necessary. In this paper we present a short-distance teleportation protocol by which an unknown three-qubit state can be transferred with the help of auxiliary qubits and a maximally entangled Bell State. In the second part of the paper we introduce a probabilistic short-distance protocol for the same unknown three-qubit state by using a non-maximally entangled Bell-state. The success probability of the protocol is calculated and its relation with the first protocol is discussed. We presented a circuit diagram for the first protocol and executed it in the IBM-Quantum platform.

Our current observations have not definitively determined the exact form of the expansion factor of spacetime. It is possible that we are experiencing a transitional stage of expansion, characterized by a combination of inflation and power-law expansion. We consider spatially homogeneous tachyon scalar fields, quintessence, and phantom fields as potential candidates for dynamical dark energy. The time-dependent potentials and fields of these three classes of scalar fields are calculated for three different mixed forms of the scale factor of expansion: firstly, a logarithmic function of time; secondly, a linear combination of power law functions of time; and thirdly, a product of power law and exponential functions of time, respectively.

In this work, we investigate the exact solutions of (2+1)-dimensional coupled resonant Davey-Stewartson equation (DSE) with the properties of truncated M-fractional derivative. It is a significant equation system that models wave packets in different fields. DSE and its coupling with other system have interesting properties and many applications in the fields of nonlinear sciences. The concept of resonant is quite important in optics, plasma physics, magneto-acoustic waves and fluid dynamics. In order to use newly designed integration method known as modified Sardar subequation method (MSSEM), we first convert the (2+1)-dimensional fractional coupled resonant DSE into a set of nonlinear ordinary diferential equations. To acquire the exact solutions, the ordinary differential equation is solved by applying the homogeneous balance method between the highest power terms and the highest derivative of the ordinary differential equation. The optical soliton solutions of the resultant system are investigated using different cases and physical constant values. The aforementioned technique is applied to the considered model, yielding several kinds of soliton solutions, such as mixed, dark, singular, bright-dark, bright, complex and combined solitons. In addition, exponential, periodic, and hyperbolic solutions are also obtained. Also, we plot the 2D, and 3D graphs with the associated parameter values to visualize the solutions. The findings of this work will help to identify and clarify some novel soliton solutions and it is expected that the solutions obtained will play a vital role in the fields of physics and engineering.

The Schrödinger equation for diatomic molecules in deSitter and anti-deSitter spaces is studied using the extended uncertainty principle formulation. The equations are solved by the Nikiforov-Uvarov method for both the Kratzer potential and the pseudoharmonic oscillator. The energy eigenvalues of the system have been derived analytically, and the exact expressions of the eigenfunctions are provided in terms of Romanovski and Jacobi polynomials. The impact of the spatial deformation parameter on the bound states is also examined, with experimental results used to establish an upper limit for this parameter.

We investigate a conditional quantum state preparation process for a generalized form of the ‘near states’ in various representations. We derive transformation rules for the analytical representation of pure states. Additionally, we obtain transformation rules for both the Glauber-Sudarshan and Wigner representations of states. The latter is particularly convenient for calculating the output state when dealing with mixed states. Furthermore, we demonstrate that small thermal noises can effectively increase success probability without compromising the nonclassical properties of the output state.

Secure multiparty computation is crucial in ensuring effective protection of participant’s privacy. Quantum homomorphic encryption technology is an effective method to facilitate the realization of quantum secure multiparty computation. The logical AND operation is a basic primitive of logical computation, often combined with the NOT operation to perform more complex logical operations. In the field of quantum computing, the Toffoli gate (composed of Clifford gate and T gate) required to implement the logical AND operation has relatively high requirements for the number and computational depth of T gates. This paper proposes a secure multiparty logical AND protocol that effectively reduces the usage and depth of T gates. Compared with previous quantum homomorphic encryption schemes, this protocol improves security based on quantum one time pad encryption and quantum teleportation, and can effectively resist various external and internal security threats including tampering attacks. The introduced quantum state commitment and auxiliary bit mechanism provides support for verifying the correctness of the calculation results. Subsequently, two important applications are derived: quantum multiparty private set intersection and quantum secure multiparty sum algorithm. Tests performed on the IBM Qiskit quantum simulator show the expected effectiveness of our method. The secure multiparty logical AND algorithm proposed in this paper is expected to be widely used in other secure multiparty computation scenarios.

Quantum coherence and quantum steering are extremely useful resources for quantum information technology. Based on the correlation between quantum coherence and quantum steering, the steered quantum coherence (SQC) is formed, which is a new quantum correlation measurement method. In this paper, the SQC is applied to explore the dynamic evolution of quantum correlation in non-Markovian systems and it is also compared with typical quantum entanglement (QE). The results show that same as the QE, the SQC can also measure the quantum correlation of quantum system. Further research shows that there are obvious differences between the two measurement methods: on the one hand, in the process of non-Markovian dynamics evolution, death and rebirth occur for QE, but not for SQC, which indicates that SQC is more robust than QE; on the other hand, the superposition effect of the channel is not conducive to maintaining the QE of the system, but it is beneficial to maintaining the SQC.

In this paper, we employ some ansatz transformations to investigate various nonlinear waves for a well-known model, the generalized reaction Duffing model, including lump soliton, rogue waves, breather waves, Ma-breather, and Kuznetsov-Ma-breather. The standard Duffing equation is expanded upon in the generalized Duffing model, which adds more terms to take into consideration for more complex behaviors. The generalized reaction Duffing model is useful in many domains, such as electrical engineering, biomechanics, climate research, seismic research, chaos theory, and many more, due to its rich behavior and nonlinear dynamic. Lump soliton is a robust, confined, self-reinforcing wave solution to non linear partial differential equations. Breather waves are periodic, specific solutions in nonlinear wave systems that preserve their amplitude and structure. Rogue waves, which pose a hazard to marine safety, are unexpectedly strong and sharp ocean surface waves that diverge greatly from the surrounding wave pattern. They frequently appear in solitary and apparently random situations. The solutions are graphically displayed using contour, 3D, and 2D graphs.

We explore the thermal properties of a system including a single-mode cavity interacting with a two-level atom at temperature T under the effect of the Stark shift. Thus, the partition function and then the thermal density matrix of the atom-field system will be needed. Using the generators of the (varvec{su(1,1)}) algebra, we first compute the total excitation number which commutes with the Hamiltonian of the system. Considering the total excitation number, the Hamiltonian is represented by a block diagonal matrix. We solve exactly our model and calculate the energy eigenvalues and corresponding eigenstates. We analyze the fidelity as numerical criterion of the closeness of the thermal atom-cavity system at two temperatures. The effect of the Stark shift coefficients on the fidelity can be studied. Moreover, we will examine the thermodynamical properties of the thermal atom-field system using the Helmholtz free energy, entropy, internal energy and heat capacity. The dependence of the temperature and Stark shift parameters on the thermodynamical properties will be discussed.

We propose a scheme to realize the robust optimal probabilistic quantum cloning (PQC) in Rydberg atoms. To enhance the robustness of the PQC circuit, we combine the nonadiabatic holonomic quantum computation (NHQC) method with super-robust dynamically corrected pulses. Our numerical simulations show that our scheme achieves high cloning fidelities under decoherence better than those of the previous scheme. Moreover, our method demonstrates excellent performance against decoherence and the X error. Overall, our approach is promising for robust PQC.