Anand K. Jha

Bio: Anand K. Jha is an academic researcher from Indian Institute of Technology Kanpur. The author has contributed to research in topics: Quantum entanglement & Spontaneous parametric down-conversion. The author has an hindex of 18, co-authored 77 publications receiving 1720 citations. Previous affiliations of Anand K. Jha include Indian Institutes of Technology & Texas A&M International University.

Quantum correlations in optical angle-orbital angular momentum variables

Abstract: Entanglement of the properties of two separated particles constitutes a fundamental signature of quantum mechanics and is a key resource for quantum information science. We demonstrate strong Einstein, Podolsky, and Rosen correlations between the angular position and orbital angular momentum of two photons created by the nonlinear optical process of spontaneous parametric down-conversion. The discrete nature of orbital angular momentum and the continuous but periodic nature of angular position give rise to a special sort of entanglement between these two variables. The resulting correlations are found to be an order of magnitude stronger than those allowed by the uncertainty principle for independent (nonentangled) particles. Our results suggest that angular position and orbital angular momentum may find important applications in quantum information science.

Audit Fees and Social Capital

Abstract: We examine the impact of social capital on audit fees. We find that firms headquartered in U.S. counties with high social capital pay lower audit fees. Social capital measures the level of mutual trust in a region. Our results suggest that auditors judge the trustworthiness of their clients based on where the firm is headquartered and charge a premium when they trust the firm less. The basis of our results is the examination of more than 28,000 audit fees for more than 5,000 firms spanning the period of 2000 to 2009. The results are robust to controlling for a large number of firm-level and county-level characteristics. JEL Classifications: M42; M14.

Corporate social responsibility and social capital

Abstract: When corporations make an effort to be socially responsible beyond what is required by the law, this effort is often described as strategic—made mainly for the shareholders’ or managers’ benefit. A large body of literature corroborates this belief. But, could the incentives for corporate social responsibility (CSR) come from an altruistic inclination fostered by the social capital of the region in which the firm is headquartered? We investigate whether this phenomenon exists by examining the association between the social capital in the region and the firm’s CSR. We find that a firm from a high social capital region exhibits higher CSR. This result suggests that the self-interest of shareholders or mangers does not explain all of the firm’s CSR, but the altruistic inclination from the region might also play a role.

Violation of a Bell inequality in two-dimensional orbital angular momentum state-spaces

Abstract: We observe entanglement between photons in controlled superposition states of orbital angular momentum (OAM). By drawing a direct analogy between OAM and polarization states of light, we demonstrate the entangled nature of high order OAM states generated by spontaneous downconversion through violation of a suitable Clauser Horne Shimony Holt (CHSH)-Bell inequality. We demonstrate this violation in a number of two-dimensional subspaces of the higher dimensional OAM Hilbert space.

Financial Reports and Social Capital

Abstract: I examine social capital’s impact on financial reports. Based on the social capital literature, I predict that the quality of the financial reports is higher when a firm is headquartered in a region with high social capital. Consistent with this prediction, I find that the firms that are headquartered in this type of region in the USA have a lower probability of committing fraud by misrepresenting financial information. Further, I find that the firms in regions with high social capital have lower levels of discretionary accruals and much more readable annual reports.

Terabit free-space data transmission employing orbital angular momentum multiplexing

Abstract: Researchers demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum — a development that provides new opportunities for increasing the data capacity of free-space optical communications links.

Evolution and Rationality Some Recent Game-Theoretic Results. Identification and Estimation of Local Average Treatment Effects

Abstract: We investigate conditions sufficient for identification of average treatment effects using instrumental variables. First we show that the existence of valid instruments is not sufficient to identify any meaningful average treatment effect. We then establish that the combination of an instrument and a condition on the relation between the instrument and the participation status is sufficient for identification of a local average treatment effect for those who can be induced to change their participation status by changing the value of the instrument. Finally we derive the probability limit of the standard IV estimator under these conditions. It is seen to be a weighted average of local average treatment effects.

Orbital angular momentum: origins, behavior and applications

Abstract: As they travel through space, some light beams rotate. Such light beams have angular momentum. There are two particularly important ways in which a light beam can rotate: if every polarization vector rotates, the light has spin; if the phase structure rotates, the light has orbital angular momentum (OAM), which can be many times greater than the spin. Only in the past 20 years has it been realized that beams carrying OAM, which have an optical vortex along the axis, can be easily made in the laboratory. These light beams are able to spin microscopic objects, give rise to rotational frequency shifts, create new forms of imaging systems, and behave within nonlinear material to give new insights into quantum optics.

The Quantum Theory of Light

Abstract: (b) Write out the equations for the time dependence of ρ11, ρ22, ρ12 and ρ21 assuming that a light field interaction V = -μ12Ee iωt + c.c. couples only levels |1> and |2>, and that the excited levels exhibit spontaneous decay. (8 marks) (c) Under steady-state conditions, find the ratio of populations in states |2> and |3>. (3 marks) (d) Find the slowly varying amplitude ̃ ρ 12 of the polarization ρ12 = ̃ ρ 12e iωt . (6 marks) (e) In the limiting case that no decay is possible from intermediate level |3>, what is the ground state population ρ11(∞)? (2 marks) 2. (15 marks total) In a 2-level atom system subjected to a strong field, dressed states are created in the form |D1(n)> = sin θ |1,n> + cos θ |2,n-1> |D2(n)> = cos θ |1,n> sin θ |2,n-1>

Optical communications using orbital angular momentum beams

Abstract: Orbital angular momentum (OAM), which describes the “phase twist” (helical phase pattern) of light beams, has recently gained interest due to its potential applications in many diverse areas. Particularly promising is the use of OAM for optical communications since: (i) coaxially propagating OAM beams with different azimuthal OAM states are mutually orthogonal, (ii) inter-beam crosstalk can be minimized, and (iii) the beams can be efficiently multiplexed and demultiplexed. As a result, multiple OAM states could be used as different carriers for multiplexing and transmitting multiple data streams, thereby potentially increasing the system capacity. In this paper, we review recent progress in OAM beam generation/detection, multiplexing/demultiplexing, and its potential applications in different scenarios including free-space optical communications, fiber-optic communications, and RF communications. Technical challenges and perspectives of OAM beams are also discussed.