The influence of atomic dipole–dipole interaction on the dynamics of the population inversion and entanglement of two atoms interacting non-resonantly with two coupled modes field

2017 ◽  
Vol 31 (05) ◽  
pp. 1750038 ◽  
Author(s):  
Elham Faraji ◽  
Hamid Reza Baghshahi ◽  
Mohammad Kazem Tavassoly
Keyword(s):  
Population Inversion ◽  
Initial Conditions ◽  
Resonance Condition ◽  
Dipole Interaction ◽  
Resonant Interaction ◽  
Von Neumann Entropy ◽  
Coupled Modes ◽  
Von Neumann ◽  
Atomic Dipole ◽  
Down Conversion

In this paper, the non-resonant interaction of two two-level atoms with two quantized cavity fields is studied by considering the dipole–dipole interaction between the two atoms. The correlation between the fields has been taken into account and the parametric down conversion is considered. Under certain initial conditions which is determined for the atoms and the fields, the analytical solution for the time-dependent Schrödinger equation is obtained. Employing this solution, we are able to discuss about some physical properties such as atomic population inversion and entanglement between various subsystems, i.e. “atoms–fields” and “atom–atom” by using respectively von Neumann entropy and negativity. It is deduced from the numerical results that, the mentioned quantities can be controlled by the atomic dipole–dipole interaction and detuning parameter, appropriately. The results show that the degree of entanglement between the two atoms is increased due to the presence of dipole–dipole coupling of the atoms at the beginning of atom–field interaction. Furthermore, it is found that, in the non-resonance condition, the so-called entanglement sudden death occurs in the presence of dipole–dipole interaction.

scholarly journals Entanglement and geometric phase of the coherent field interacting with a three two-level atoms in the presence of non-linear terms

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 237-245
Author(s):  
Eman Hilal ◽  
Sadah Alkhateeb ◽  
Sayed Abel-Khalek ◽  
Eied Khalil ◽  
Amjaad Almowalled
Keyword(s):  
Coherent State ◽  
Geometric Phase ◽  
Initial Conditions ◽  
Von Neumann Entropy ◽  
Field Mode ◽  
Von Neumann ◽  
Coherent Field ◽  
Non Linear ◽  
Atomic States ◽  
The Impact

We study the interaction of a three two-level atoms with a one-mode optical coherent field in coherent state in the presence of non-linear Kerr medim. The three atoms are initially prepared in upper and entangled states while the field mode is in a coherent state. The constants of motion, three two-level atoms and field density matrix are obtained. The analytic results are employed to perform some investigations of the temporal evolution of the von Neumann entropy as measure of the degree of entanglement between the three two-level atoms and optical coherent field. The effect of the detuning and the initial atomic states on the evolution of geometric phase and entanglement is analyzed. Also, we demonstrate the link between the geometric phase and non-classical properties during the evolution time. Additionally the effect of detuning and initial conditions on the Mandel parameter is studied. The obtained results are emphasize the impact of the detuning and the initial atomic states of the feature of the entanglement, geometric phase and photon statistics of the optical coherent field.

On the interaction between a time-dependent field and a two-level atom

2019 ◽  
Vol 34 (10) ◽  
pp. 1950081 ◽  
Author(s):  
N. H. Abdel-Wahab ◽  
Ahmed Salah
Keyword(s):  
Quantum Electrodynamics ◽  
Initial Conditions ◽  
Coupling Parameter ◽  
Quantum Systems ◽  
Trapped Ions ◽  
Time Dependent ◽  
Von Neumann Entropy ◽  
Von Neumann ◽  
Level Atom ◽  
Dependent Field

In this paper, we study the interaction between the time-dependent field and a two-level atom with one mode electromagnetic field. We consider that the field of photons is assumed to be coupled with modulated coupling parameter which depends explicitly on time. It is shown that the considered model can be reduced to a well-known form of the time-dependent generalized Jaynes–Cummings model. Under special initial conditions, in which the atom and the field are prepared in the excited and the coherent states, respectively, the explicit time evolution of the wave function of the entire system is analytically obtained. Our proposal has many advantages over the previous optical schemes and can be realized in several multiple experiments, such as trapped ions and quantum electrodynamics cavity. The influence of the time-dependent field parameter on the collapses-revivals, the normal squeezing of the radiation, the anti-bunching of photons and the entanglement phenomena for the considered atomic system is examined. The linear entropy, the von Neumann entropy are used to quantify entanglement in the quantum systems. We noticed that these phenomena are affected by the existence of both the time-dependent coupling field and detuning parameters.

scholarly journals Entanglement and geometric phase of the coherent field interacting with a three two-level atoms in the presence of non-linear terms

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 237-245
Author(s):  
Eman Hilal ◽  
Sadah Alkhateeb ◽  
Sayed Abel-Khalek ◽  
Eied Khalil ◽  
Amjaad Almowalled
Keyword(s):  
Coherent State ◽  
Geometric Phase ◽  
Initial Conditions ◽  
Von Neumann Entropy ◽  
Field Mode ◽  
Von Neumann ◽  
Coherent Field ◽  
Non Linear ◽  
Atomic States ◽  
The Impact

We study the interaction of a three two-level atoms with a one-mode optical coherent field in coherent state in the presence of non-linear Kerr medim. The three atoms are initially prepared in upper and entangled states while the field mode is in a coherent state. The constants of motion, three two-level atoms and field density matrix are obtained. The analytic results are employed to perform some investigations of the temporal evolution of the von Neumann entropy as measure of the degree of entanglement between the three two-level atoms and optical coherent field. The effect of the detuning and the initial atomic states on the evolution of geometric phase and entanglement is analyzed. Also, we demonstrate the link between the geometric phase and non-classical properties during the evolution time. Additionally the effect of detuning and initial conditions on the Mandel parameter is studied. The obtained results are emphasize the impact of the detuning and the initial atomic states of the feature of the entanglement, geometric phase and photon statistics of the optical coherent field.

Damping, field–field correlation and dipole–dipole interaction effects on the entanglement and atomic inversion dynamics

2017 ◽  
Vol 31 (03) ◽  
pp. 1750006
Author(s):  
N. Rustaee ◽  
M. K. Tavassoly ◽  
R. Daneshmand
Keyword(s):  
Population Inversion ◽  
Dynamical Behavior ◽  
Dipole Interaction ◽  
Time Behavior ◽  
Atomic Inversion ◽  
Atomic Dipole ◽  
Quantized Field ◽  
Damped Systems ◽  
Field Correlation ◽  
Degree Of Entanglement

In this paper we study the interaction between two two-level atoms with a two-mode quantized field in the presence of damping. Dipole–dipole interaction between the two atoms and the correlation between the two modes of field are also taken into account. To solve the model, using appropriate transformations, we reduce the considered model to a well-known Jaynes–Cummings model. After finding the analytical solution for the atom–field system, the effects of damping, field–field correlation and atomic dipole–dipole interaction on the entanglement between atoms and population inversion are investigated, numerically. It is observed that the dynamical behavior of the degree of entanglement for damped systems, in relatively large domains of time, takes a low but constant value adequately far from the beginning of the interaction. In addition, it is found that the value of population inversion after the initial oscillations takes negative values for damped systems and eventually vanishes by increasing time. Also, it is seen that simultaneous presence of both dipole–dipole interaction and field–field correlation provides typical collapse–revival phenomenon in the time-behavior of atomic inversion.

Information quantifiers for trapped ion in a carrier excitation laser field

2020 ◽  
Vol 35 (28) ◽  
pp. 2050235
Author(s):  
Bahaaudin M. Raffah ◽  
E. M. Khalil ◽  
S. Abdel-Khalek ◽  
K. Berrada ◽  
Yas Al-Hadeethi ◽  
...  
Keyword(s):  
External Field ◽  
Fisher Information ◽  
Geometric Phase ◽  
Laser Field ◽  
Population Inversion ◽  
Von Neumann Entropy ◽  
Von Neumann ◽  
Trapped Ion ◽  
Excitation Laser ◽  
Physical Phenomena

The laser field interacting with single trapped ion in a carrier excitation frame in the presence of an external field is investigated. Detailed analytical expressions are given, taking into account carrier excitation configurations. We study the evolution of the population inversion, fidelity, ion-field entanglement, Fisher information and the geometric phase. The results indicate the influence of the external field on the information quantities to describe some physical phenomena. The relation between the population inversion, fidelity, von Neumann entropy, Fisher information, and geometric phase are explored during the time evolution.

ASYMPTOTIC ENTANGLEMENT IN THE PARAMETRIZED HADAMARD WALK

2012 ◽  
Vol 10 (06) ◽  
pp. 1250066 ◽  
Author(s):  
CLEMENT AMPADU
Keyword(s):  
Density Operator ◽  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Von Neumann Entropy ◽  
Von Neumann ◽  
Fourier Representation ◽  
Asymptotic Entropy ◽  
Reduced Density

We study asymptotic entanglement properties of the Hadamard walk with phase parameters on the line using the Fourier representation. We use the von Neumann entropy of the reduced density operator to quantify entanglement between the coin and position degrees of freedom. We investigate obtaining exact expressions for the asymptotic entropy of entanglement, for different classes of initial conditions. We also determine under which conditions the asymptotic entropy of entanglement can be characterized as full, intermediate, or minimum.

scholarly journals Quantum reversibility is relative, or does a quantum measurement reset initial conditions?

2018 ◽  
Vol 376 (2123) ◽  
pp. 20170315 ◽  
Author(s):  
Wojciech H. Zurek
Keyword(s):  
Quantum Dynamics ◽  
Quantum Physics ◽  
Information Gain ◽  
Initial Conditions ◽  
Foundations Of Quantum Mechanics ◽  
Von Neumann Entropy ◽  
Quantum Evolution ◽  
Von Neumann ◽  
The Universe

I compare the role of the information in classical and quantum dynamics by examining the relation between information flows in measurements and the ability of observers to reverse evolutions. I show that in the Newtonian dynamics reversibility is unaffected by the observer’s retention of the information about the measurement outcome. By contrast—even though quantum dynamics is unitary, hence, reversible—reversing quantum evolution that led to a measurement becomes, in principle, impossible for an observer who keeps the record of its outcome. Thus, quantum irreversibility can result from the information gain rather than just its loss—rather than just an increase of the (von Neumann) entropy. Recording of the outcome of the measurement resets, in effect, initial conditions within the observer’s (branch of) the Universe. Nevertheless, I also show that the observer’s friend—an agent who knows what measurement was successfully carried out and can confirm that the observer knows the outcome but resists his curiosity and does not find out the result—can, in principle, undo the measurement. This relativity of quantum reversibility sheds new light on the origin of the arrow of time and elucidates the role of information in classical and quantum physics. Quantum discord appears as a natural measure of the extent to which dissemination of information about the outcome affects the ability to reverse the measurement. This article is part of a discussion meeting issue ‘Foundations of quantum mechanics and their impact on contemporary society’.

scholarly journals Spectral Structure and Many-Body Dynamics of Ultracold Bosons in a Double-Well

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 382
Author(s):  
Frank Schäfer ◽  
Miguel A. Bastarrachea-Magnani ◽  
Axel U. J. Lode ◽  
Laurent de Forges de Parny ◽  
Andreas Buchleitner
Keyword(s):  
Initial Conditions ◽  
Dynamical Behavior ◽  
Particle Interaction ◽  
Interaction Strength ◽  
Von Neumann Entropy ◽  
Spectral Structure ◽  
Many Body ◽  
Point Energy ◽  
Von Neumann ◽  
Body Dynamics

We examine the spectral structure and many-body dynamics of two and three repulsively interacting bosons trapped in a one-dimensional double-well, for variable barrier height, inter-particle interaction strength, and initial conditions. By exact diagonalization of the many-particle Hamiltonian, we specifically explore the dynamical behavior of the particles launched either at the single-particle ground state or saddle-point energy, in a time-independent potential. We complement these results by a characterization of the cross-over from diabatic to quasi-adiabatic evolution under finite-time switching of the potential barrier, via the associated time evolution of a single particle’s von Neumann entropy. This is achieved with the help of the multiconfigurational time-dependent Hartree method for indistinguishable particles (MCTDH-X)—which also allows us to extrapolate our results for increasing particle numbers.

scholarly journals Islands in linear dilaton black holes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Georgios K. Karananas ◽  
Alex Kehagias ◽  
John Taskas
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Entanglement Entropy ◽  
Von Neumann Entropy ◽  
Two Dimensional ◽  
Extremal Case ◽  
Von Neumann ◽  
Dimensional Black Hole ◽  
Linear Dilaton ◽  
Linear Dilaton Black Hole

Abstract We derive a novel four-dimensional black hole with planar horizon that asymptotes to the linear dilaton background. The usual growth of its entanglement entropy before Page’s time is established. After that, emergent islands modify to a large extent the entropy, which becomes finite and is saturated by its Bekenstein-Hawking value in accordance with the finiteness of the von Neumann entropy of eternal black holes. We demonstrate that viewed from the string frame, our solution is the two-dimensional Witten black hole with two additional free bosons. We generalize our findings by considering a general class of linear dilaton black hole solutions at a generic point along the σ-model renormalization group (RG) equations. For those, we observe that the entanglement entropy is “running” i.e. it is changing along the RG flow with respect to the two-dimensional worldsheet length scale. At any fixed moment before Page’s time the aforementioned entropy increases towards the infrared (IR) domain, whereas the presence of islands leads the running entropy to decrease towards the IR at later times. Finally, we present a four-dimensional charged black hole that asymptotes to the linear dilaton background as well. We compute the associated entanglement entropy for the extremal case and we find that an island is needed in order for it to follow the Page curve.

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