ترغب بنشر مسار تعليمي؟ اضغط هنا

Generation of macroscopic entangled cat states in a molecular cavity-QED system

104   0   0.0 ( 0 )
 نشر من قبل Jie-Qiao Liao
 تاريخ النشر 2019
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Macroscopic entangled cat states not only are significant in the demonstration of the fundamentals of quantum physics, but also have wide applications in modern quantum technologies such as continuous-variable quantum information processing and quantum metrology. Here we propose a scheme for generation of macroscopic entangled cat states in a molecular cavity-QED system, which is composed of an organic molecule (including electronic and vibrational states) coupled to a single-mode cavity field. By simultaneously modulating the resonance frequencies of the molecular vibration and the cavity field, the molecular vibrational displacement can be enhanced significantly and hence macroscopic entangled cat states between the molecular vibrational mode and the cavity mode can be created. We also study quantum coherence effects in the generated states by calculating the joint Wigner function and the degree of entanglement. The dissipation effects are included by considering the state generation in the open-system case. Our results will pave the way to the study of quantum physics and quantum chemistry in molecular cavity-QED systems.

قيم البحث

اقرأ أيضاً

We present an efficient method to generate a Greenberger-Horne-Zeilinger (GHZ) entangled state of three cat-state qubits (cqubits) via circuit QED. The GHZ state is prepared with three microwave cavities coupled to a superconducting transmon qutrit. Because the qutrit remains in the ground state during the operation, decoherence caused by the energy relaxation and dephasing of the qutrit is greatly suppressed. The GHZ state is created deterministically because no measurement is involved. Numerical simulations show that high-fidelity generation of a three-cqubit GHZ state is feasible with present circuit QED technology. This proposal can be easily extended to create a $N$-cqubit GHZ state ($Ngeq 3$), with $N$ microwave or optical cavities coupled to a natural or artificial three-level atom.
68 - Z. Xiao , T. Fuse , S. Ashhab 2018
We study a qubit-oscillator system, with a time-dependent coupling coefficient, and present a scheme for generating entangled Schrodinger-cat states with large mean photon numbers and also a scheme that protects the cat states against dephasing cause d by the nonlinearity in the system. We focus on the case where the qubit frequency is small compared to the oscillator frequency. We first present the exact quantum state evolution in the limit of infinitesimal qubit frequency. We then analyze the first-order effect of the nonzero qubit frequency. Our scheme works for a wide range of coupling strength values, including the recently achieved deep-strong-coupling regime.
A Macro-state consisting of N= 3.5 x 10^4 photons in a quantum superposition and entangled with a far apart single-photon state (Micro-state) is generated. Precisely, an entangled photon pair is created by a nonlinear optical process, then one photon of the pair is injected into an optical parametric amplifier (OPA) operating for any input polarization state, i.e. into a phase-covariant cloning machine. Such transformation establishes a connection between the single photon and the multi particle fields. We then demonstrate the non-separability of the bipartite system by adopting a local filtering technique within a positive operator valued measurement.
A theoretical scheme is presented for the adiabatic generation of N-quNit singlet states with $Ngeqslant3$, which may be more feasible than previous ones in a cavity. In this proposal, the system may be robust both parameter fluctuations and dissipat ion along a dark state. In addition, quantum information is only stored in atomic ground states and there is no energy exchanged between atoms and photons in a cavity so as to reduce the influence of atomic spontaneous emission and cavity decays.
The paradigm of Schr{o}dingers cat illustrates how quantum states preclude the assignment of definite properties to a macroscopic object (realism). In this work we develop a method to investigate the indefiniteness of cat states using currently avail able cold atom technology. The method we propose uses the observation of a statistical distribution to demonstrate the macroscopic distinction between dead and alive states, and uses the determination of the interferometric sensitivity (Fisher information) to detect the indefiniteness of the cats vital status. We show how combining the two observations can provide information about the structure of the quantum state without the need for full quantum state tomography, and propose a measure of the indefiniteness based on this structure. We test this method using a cat state proposed by Gordon and Savage [Phys. Rev. A 59, 4623 (1999)] which is dynamically produced from a coherent state. As a control, we consider a set of states produced using the same dynamical procedure acting on an initial thermal distribution. Numerically simulating our proposed method, we show that as the temperature of this initial state is increased, the produced state undergoes a quantum to classical crossover where the indefiniteness of the cats vital status is lost, while the macroscopic distinction between dead and alive states of the cat is maintained.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا