Stationary entanglement between macroscopic mechanical oscillators

We show that the optomechanical coupling between an optical cavity mode and two movable cavity mirrors is able to entangle two different macroscopic oscillation modes of the mirrors. This continuous variable entanglement is maintained by the light bouncing between the mirrors and is robust against thermal noise. In fact, it could be experimentally demonstrated using present technology. Received 2 September 2002 / Received in final form 10 October 2002 Published online 7 January 2003     

Application of solid-phase microextraction combined with gas chromatography-mass spectrometry to the determination of butylated hydroxytoluene in bottled drinking water

Butylated hydroxytoluene (BHT) is an antioxidant utilized as additive in foods and packaging plastic. Its presence in drinking water is possible if it is used as an antioxidant in the packaging plastic because it may migrate into the package's contents. A method for the determination of BHT in water by means of solid-phase microextraction and gas chromatography-mass spectrometry has been developed and evaluated with respect to the time of fiber exposure, limits of detection and quantitation, linearity and precision. Finally, the method was applied to evaluate the presence of this substance in samples of mineral and mineralized bottled drinking water, and it appeared to be present in seven out of a total of fifteen commercial brands.     

Monoclonal antibodies as a tool for structure-function studies of the MDR1-P-glycoprotein

P-glycoprotein is considered one of the most important member of the rapidly growing superfamily of integral proteins known as the ATP-binding cassette (ABC) which in human also include several other multidrug resistance membrane proteins (i.e., MRP), the product of the cystic fibrosis gene, the TAP-1/TAP2 peptide transporters encoded by the major histocompatibility complex genes and the gene encoding for breast cancer resistance protein (BCRP) also known as MXR1 (mitoxantrone resistance protein). Many monoclonal antibodies (MAbs) reacting with distinct P-glycoprotein domains have been isolated and used to study the molecular organization and cellular functions of this ABC protein. MAbs have been used for multidrug resistance (mdr) gene cloning, delineation of the secondary and tertiary structure of P-glycoprotein and molecular analysis of the mechanisms involved in substrate recognition and transport. The immunodetection of the distinct products of the mdr gene family in normal and malignant cells and tissues has greatly contributed to the understanding of the physiological role of P-glycoprotein and its possible involvement in the refractory of tumors to chemotherapy. The present article deals with the immunological methods used for the structure-function studies of the P-glycoprotein. After introducing the basic structural features of this ABC transporter, the antibody based-approach is discussed with aiming to furnishing methodological perspectives for further investigations of the physiological role of P-glycoprotein and the multidrug resistance phenomenon.     

Entangling macroscopic oscillators exploiting radiation pressure

It is shown that radiation pressure can be profitably used to entangle macroscopic oscillators like movable mirrors, using present technology. We prove a new sufficient criterion for entanglement and show that the achievable entanglement is robust against thermal noise. Its signature can be revealed using common optomechanical readout apparatus.     

Scheme for teleportation of quantum states onto a mechanical resonator

We propose an experimentally feasible scheme to teleport an unkown quantum state onto the vibrational degree of freedom of a macroscopic mirror. The quantum channel between the two parties is established by exploiting radiation pressure effects.     

Continuous variable encoding by ponderomotive interaction

Recently it has been proposed to construct quantum error-correcting codes that embed a finite-dimensional Hilbert space in the infinite-dimensional Hilbert space of a system described by continuous quantum variables [D. Gottesman et al., Phys. Rev. A 64, 012310 (2001)]. The main difficulty of this continuous variable encoding relies on the physical generation of the quantum codewords. We show that ponderomotive interaction suffices to this end. As a matter of fact, this kind of interaction between a system and a meter causes a frequency change on the meter proportional to the position quadrature of the system. Then, a phase measurement of the meter leaves the system in an eigenstate of the stabilizer generators, provided that system and meter's initial states are suitably prepared. Here we show how to implement this interaction using trapped ions, and how the encoding can be performed on their motional degrees of freedom. The robustness of the codewords with respect to the various experimental imperfections is then analyzed.     

Experimental test of two-way quantum key distribution in the presence of controlled noise

We describe the experimental test of a quantum key distribution performed with a two-way protocol without using entanglement. An individual incoherent eavesdropping is simulated and induces a variable amount of noise on the communication channel. This allows a direct verification of the agreement between theory and practice.     

Entanglement from ponderomotive interaction

A simple interaction model is employed to show that radiation pressure effects, i.e., ponderomotive effects, can be profitably used to entangle radiation fields, as well as macroscopic oscillators such as movable mirrors.