May 3: Degradation of Quantum Entanglement in Optical Amplifier

This Friday, Bhaskar Roy Bardhan is going to give us a talk. As usual, food and drink will be available at 11:30AM.

Degradation of Quantum Entanglement in Optical Amplifier

Abstract:

We analyze the effect of the quantum noise of an amplifier on the entanglement properties of an input state. We consider both phase insensitive and phase sensitive amplification and specialize to Gaussian states for which entanglement measures are well developed. In the case of phase insensitive amplification in which both the modes are symmetrically amplified, we find that the entanglement in the output state vanishes if the intensity gain exceeds a limiting value 2/(1+exp[-EN]) where EN is the logarithmic negativity of the input state which quantifies the initial entanglement between the two modes. The entanglement between the two modes at the output is found to be more robust if only one mode is amplified.

Articles to be discussed:

S. Lloyd, Science 321, 5895 pp. 1463-1465 (2008).
G.S. Agarwal and S. Chaturvedi, Optics Communications 283, 839 (2010).

Time: Friday, May 3, 11:30AM
Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 11:30AM.

Apr 26: Entangled Photon Holes: A New Possibility for Robust Quantum Information Processing?

This Friday, we will have a talk by Kaushik Seshadreesan, the first Quantum Optics talk in this semester. Please note that the meeting this week is 1 hour later than usual, i.e. 12:30pm-1:30pm, due to conflict with a class. Food and drink will be provided.

Title: "Entangled Photon Holes: A New Possibility for Robust Quantum Information Processing?"

Abstract: 

States of the radiation field with correlated absence of photons called entangled photon 'holes' may open new doors in quantum communication and computation, as well as fundamental quantum studies. In contrast to entangled photon pairs, the holes exist in an optical background that may be less susceptible to decoherence, while still allowing for nonclassical effects. I will discuss the generation of entangled photon holes and show that, in the ideal case of no decoherence, their addition in fact enhances the entanglement content of a priori entangled optical states.

References:

Phys. Rev. A 74, 041801(R) (2006).
Phys. Rev. Lett. 96, 090402 (2006).
Phys. Rev. Lett. 105, 093603 (2010).

Time: Friday, Apr 26, 12:30pm
Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 12:30pm.

Apr 19: Results from the Pierre Auger Observatory

This Friday (Apr 19), Azadeh Keivani will introduce the latest results from the Pierre Auger Observatory. Food and drink will be provided.

Title:
Results from the Pierre Auger Observatory

Abstract:
Pierre Auger Observatory (PAO) is an ultra-high energy cosmic ray observatory located in Argentina. If you want to know more about cosmic rays and operation of the PAO , come to this talk! I will tell you about the interesting results we have got so far!

Related Journal Articles:
http://adsabs.harvard.edu/abs/2012PhRvL.109f2002A
http://adsabs.harvard.edu/abs/2010PhRvL.104i1101A
http://adsabs.harvard.edu/abs/2007Sci...318..938P

Time: Friday, Apr 19, 11:30AM
Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 11:30AM.

Mar 15: Special Session: Rehearsal for APS March Meeting

Mar 15: Special Session: Rehearsal for APS March Meeting

We are having APS March meeting rehearsal this week too. Following APS format, presentation will be 10 minutes with 2 minutes of questions.

The speakers who will attend the Mar 15 session are:

Qinqin

Niladri Sengupta

Drew Rebar

Conrad Moore

Yang Shuxiang

Peng Zang

Ryky Nelson

If anyone else is ready to give the talk, please let us know before the meeting begins.

Rehearsal for APS Meeting

Time: Friday, Mar 15, 11:30AM

Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 11:30AM.

Mar 8: Special Session: Rehearsal for APS March Meeting

On Mar 8 and Mar 15, we will hold two special sessions for the people who will attend the APS March Meeting to practice their talks. The speakers who will attend the Mar 8 session are:

Kuang-Shing Chen
Ziyang Meng
Neel Haldolaarachchige
Kalani Hettiarachchilage

If you feel ready to give the talk, please let us know anytime before the meeting begins. We should be able to accomodate as many as 8 people.

This session will strictly follow the APS convention, i.e. 10 minute talk and 2 minute question time for each speaker.

And, as usual, food and drink will be provided at 11:30AM.

Rehearsal for APS Meeting

Time: Friday, Mar 8, 11:30AM

Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 11:30AM.

Mar 1: A Spectral Analysis of the Galactic Bulge Survey X-ray Source CX514

On Mar 1, Christopher Johnson will give us a talk about:

A Spectral Analysis of the Galactic Bulge Survey X-ray Source CX514

The speaker will begin by giving some background information on the Galactic Bulge Survey (GBS) and then focus on one source in particular, CX514. 

Abstract:

We present the spectroscopic and photometric results of the Galactic Bulge Survey (GBS) optical counterpart of the X-ray source CXOGBS J175637.0-271145 (CX514). A refinement of the spectral classification of CX514 has revealed an effective temperature of about 15,000 K and log g = 4.0 which indicates a B6V classification and is unlike the previously labeled B9 classification. A spectroscopic period search of the radial velocity curve revealed a period of 1.3740(61) days which differs from the photometric period found to be 0.8895214(52) days. With the calculation of the dynamic parameters from the radial velocity curve, we find an X-ray source mass of 0.8-0.9 solar masses. This mass constraint, along with the absence of emission in the optical spectra indicates either a white dwarf primary source or an active main sequence type star.

Related paper (not on the exactly same topic, but contains all essential information):

http://arxiv.org/pdf/1211.1040v1.pdf

Speaker: Christopher Johnson

Time: Friday, Mar 1, 11:30AM

Location: Rm 201, Nicholson Hall

Foods and drinks will be provided at 11:30AM.

Feb 22: Identification of 5 Interacting Binaries in the Galactic Bulge Survey

Identification of 5 Interacting Binaries in the Galactic Bulge Survey

We present optical lightcurves, spectroscopy, and classification of five X-ray s ources in the Chandra Galactic Bulge Survey [CXOGBS J174009.1-284725 (CX5), CXOG BS J173935.7-272935 (CX18), CXOGBS J173946.9-271809 (CX28), CXOGBS J173729.1-292 804 (CX37), CXOGBS J174607.6-261547 (CX561)]. These objects were selected based on bright optical counterparts which were quickly found to have emission lines in their optical spectra. This paper presents an illustration of GBS optical follow-up, targeting emission line objects. Of these five objects, four exhibit phot ometric variability in the Sloan $r'$ band. CX5 shows a tentative period of 2.1 hours and is clearly an IP. CX28 and CX37 both exhibit flickering with no clear period. Both are suggested to also be IPs. CX18 was observed to undergo 2 dwarf nova outbursts. Finally, CX561 shows no detectable variability, although its characteristics would be consistent with either a quiescent LMXB or CV.

link to paper

Speaker: Christopher Britt

Time: Friday, Feb 22, 11:30AM

Location: Rm 201, Nicholson Hall

Foods and drinks will be provided.