ترغب بنشر مسار تعليمي؟ اضغط هنا

Entangling microscopic defects via a macroscopic quantum shuttle

48   0   0.0 ( 0 )
 نشر من قبل Pavel Bushev
 تاريخ النشر 2011
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

In the microscopic world, multipartite entanglement has been achieved with various types of nanometer sized two-level systems such as trapped ions, atoms and photons. On the macroscopic scale ranging from micrometers to millimeters, recent experiments have demonstrated bipartite and tripartite entanglement for electronic quantum circuits with superconducting Josephson junctions. It remains challenging to bridge these largely different length scales by constructing hybrid quantum systems. Doing this may allow for manipulating the entanglement of individual microscopic objects separated by macroscopically large distances in a quantum circuit. Here we report on the experimental demonstration of induced coherent interaction between two intrinsic two-level states (TLSs) formed by atomic-scale defects in a solid via a superconducting phase qubit. The tunable superconducting circuit serves as a shuttle communicating quantum information between the two microscopic TLSs. We present a detailed comparison between experiment and theory and find excellent agreement over a wide range of parameters. We then use the theoretical model to study the creation and movement of entanglement between the three components of the quantum system.

قيم البحث

اقرأ أيضاً

We theoretically show how two impurity defects in a crystalline structure can be entangled through coupling with the crystal. We demonstrate this with a harmonic chain of trapped ions in which two ions of a different species are embedded. Entanglemen t is found for sufficiently cold chains and for a certain class of initial, separable states of the defects. It results from the interplay between localized modes which involve the defects and the interposed ions, it is independent of the chain size, and decays slowly with the distance between the impurities. These dynamics can be observed in systems exhibiting spatial order, viable realizations are optical lattices, optomechanical systems, or cavity arrays in circuit QED.
244 - James A. Blackburn 2020
Switching current distributions have for decades been an indispensable diagnostic tool for studying Josephson junctions. They have played a key role in testing the conjecture of a macroscopic quantum state in junctions at millikelvin temperatures. Th e conventional basis of the test has been the observation of temperature independence of SCD peak widths, and that led to affirmative conclusions about a crossover. A different criterion is proposed here - the distance of the SCD peak from the junction critical current - and its efficacy is demonstrated. This test has distinct advantages in terms of precision, and it is found that, for three example experiments, the evidence for a crossover to the conjectured macroscopic quantum state is unequivocally negative. The implications of this finding for superconducting qubits are considered.
We investigate a hybrid quantum system consisting of spatially separated resonant exchange qubits, defined in three-electron semiconductor triple quantum dots, that are coupled via a superconducting transmission line resonator. Drawing on methods fro m circuit quantum electrodynamics and Hartmann-Hahn double resonance techniques, we analyze three specific approaches for implementing resonator-mediated two-qubit entangling gates in both dispersive and resonant regimes of interaction. We calculate entangling gate fidelities as well as the rate of relaxation via phonons for resonant exchange qubits in silicon triple dots and show that such an implementation is particularly well-suited to achieving the strong coupling regime. Our approach combines the favorable coherence properties of encoded spin qubits in silicon with the rapid and robust long-range entanglement provided by circuit QED systems.
We introduce a Maxwell demon which generates many-body-entanglement robustly against thermal fluctuations, which allows us to obtain quantum advantage. Adopting the protocol of the voter model used for opinion dynamics approaching consensus, the demo n randomly selects a qubit pair and performs a quantum feedback control, in continuous repetitions. We derive a lower bound of the entropy production rate by demons operation, which is determined by a competition between the quantum-classical mutual information acquired by the demon and the absolute irreversibility of the feedback control. Our finding of the lower bound corresponds to a reformulation of the second law of thermodynamics under a stochastic and continuous quantum feedback control.
255 - H. Duprez , E. Sivre , A. Anthore 2019
The quantum coherence of electronic quasiparticles underpins many of the emerging transport properties of conductors at small scales. Novel electronic implementations of quantum optics devices are now available with perspectives such as flying qubit manipulations. However, electronic quantum interferences in conductors remained up to now limited to propagation paths shorter than $30,mu$m, independently of the material. Here we demonstrate strong electronic quantum interferences after a propagation along two $0.1,$mm long pathways in a circuit. Interferences of visibility as high as $80%$ and $40%$ are observed on electronic analogues of the Mach-Zehnder interferometer of, respectively, $24,mu$m and $0.1,$mm arm length, consistently corresponding to a $0.25,$mm electronic phase coherence length. While such devices perform best in the integer quantum Hall regime at filling factor 2, the electronic interferences are restricted by the Coulomb interaction between copropagating edge channels. We overcome this limitation by closing the inner channel in micron-scale loops of frozen internal degrees of freedom, combined with a loop-closing strategy providing an essential isolation from the environment.
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