
P.S.: M&M can also be Mahindra & Mahindra. End of OT from me.
a dense ball of matter with a core of dark energy
A new world record for quantum teleportation has been set, bringing quantum communication networks that can stretch between cities a step closer. Two independent teams have transferred quantum information over several kilometres of fibre optic networks.Being able to establish teleportation over long distances is a crucial step towards exchanging quantum cryptographic keys needed for encoding data sent over the fibres.
Quantum teleportation is a phenomenon in which the quantum states of one particle can be transferred to another, distant particle without anything physical traveling between them. It relies on a property called entanglement, in which measuring the state of one particle immediately affects the state of its entangled partner, regardless of the distance between them.The record for sheer distance between Alice and Bob was set in 2012, when a group led by Anton Zeilinger at the University of Vienna achieved teleportation over 143 kilometres of free space between two of the Canary Islands. But there’s no obvious way to translate that feat into a practical quantum network that would work within a city, where free space is hard to come by and other interference would destroy delicate quantum states.Now, Wolfgang Tittel at the University of Calgary in Alberta, Canada, and colleagues have upped the ante. They extended the distance between Charlie and Bob and teleported quantum states using part of Calgary’s fibre optic network that isn’t being used for regular communications.“The distance between Charlie and Bob, that’s the distance that counts,” says Tittel. “We have shown that this works across a metropolitan fibre network, over 6.2 kilometres, as the crow flies.”Jian-Wei Pan at the University of Science and Technology of China and colleagues achieved a comparable separation between Charlie and Bob when they teleported quantum states using the city of Hefei’s fibre optic network. Their setup was slightly different, though: it was Charlie in the middle who created the entangled pair of particles and sent one to Bob, instead of the other way around.Pan’s configuration could prove useful for building a quantum network within a city, where many sets of Alice-Charlie-Bob links each communicate with a central quantum computer. But Tittel’s team argues that their setup could enable quantum communication networks that stretch between cities.
That’s because it would allow for the creation of quantum repeaters, to propel the signal further along the network. Say Alice and Bob are 100 kilometres apart, with Bob to the right of Alice. Both create a pair of entangled particles each, keep one and send the other to Charlie, who is midway between them. Charlie performs the Bell state measurement, entangling the particles still with Alice and Bob.Now say Bob repeats the process with Daisy, who is 100 kilometres to his right (with another Charlie between them). At this stage, Bob has two particles, one entangled with Alice’s and the other with Daisy’s. If Bob now does a Bell State measurement on his two particles, he effectively entangles Alice’s particle with Daisy’s — stretching teleportation a full 200 kilometres.“You can scale the whole thing up and can go, in theory, to arbitrarily long distances,” says Tittel.“The two experiments can be seen as milestones on the path to a long-term goal, namely to build a fibre-based quantum internet connecting large cities,” says Johannes Kofler at the Max Planck Institute of Quantum Optics in Munich.
Supercomputer simulations of Einstein's equations for parameters that matched with gravitational wave signal in LIGO
Zynda wrote:Not in the physics profession, so take my reply FWIW and you probably may be aware of this and might be looking for a deeper explanation/answers.
There is something called as Event Horizon (sort of no escape zone) for all black holes. Once you are inside the event horizon, nothing can escape including light hence the dark/black circles. Now the core of the black hole may be at the centre but technically the black hole starts at the event horizon (perimeter).
Hope this answers your question.
”The gathering will begin with an overview of new findings from LIGO, Virgo and partners that span the globe, followed by details from telescopes that work with the LIGO and Virgo collaborations to study extreme events in the cosmos,
VenkataS wrote:
Layman question here, why is noticing a pulse of two neutron stars merging such a big deal?
“If the detection is true, it would be transformative for the field and probably one of the greatest discoveries in astronomy,” said Enrico Ramirez-Ruiz of the University of California, Santa Cruz, who refused to discuss any specific results.
ArjunPandit wrote:Why Indian astrosat is not used for this
Zynda wrote:AmberG, what would be the outcome of two neutron stars colliding/merging? I've heard cosmologists say that result probably might be formation of a new black hole but is it possible due to the energy released from collision, the stars disintegrate and individual neutrons spread around (if such a thing could happen)? Probably using a wrong analogy here...like two planets colliding and result being shattered rocks? I hope this ain't a dumb thing to ask!
The Fate of Neutron Star Binary Mergers
Anthony L. Piro1, Bruno Giacomazzo2,3, and Rosalba Perna4
Published 2017 July 27 • © 2017. The American Astronomical Society. All rights reserved.
The Astrophysical Journal Letters, Volume 844, Number 2
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Abstract
Following merger, a neutron star (NS) binary can produce roughly one of three different outcomes: (1) a stable NS, (2) a black hole (BH), or (3) a supramassive, rotationally supported NS, which then collapses to a BH following angular momentum losses. Which of these fates occur and in what proportion has important implications for the electromagnetic transient associated with the mergers and the expected gravitational wave (GW) signatures, which in turn depend on the high density equation of state (EOS). Here we combine relativistic calculations of NS masses using realistic EOSs with Monte Carlo population synthesis based on the mass distribution of NS binaries in our Galaxy to predict the distribution of fates expected. For many EOSs, a significant fraction of the remnants are NSs or supramassive NSs. This lends support to scenarios in which a quickly spinning, highly magnetized NS may be powering an electromagnetic transient. This also indicates that it will be important for future GW observatories to focus on high frequencies to study the post-merger GW emission. Even in cases where individual GW events are too low in signal to noise to study the post merger signature in detail, the statistics of how many mergers produce NSs versus BHs can be compared with our work to constrain the EOS. To match short gamma-ray-burst (SGRB) X-ray afterglow statistics, we find that the stiffest EOSs are ruled out. Furthermore, many popular EOSs require a significant fraction of ~60%–70% of SGRBs to be from NS–BH mergers rather than just binary NSs.
Zynda wrote:AmberG, what would be the outcome of two neutron stars colliding/merging? I've heard cosmologists say that result probably might be formation of a new black hole but is it possible due to the energy released from collision, the stars disintegrate and individual neutrons spread around (if such a thing could happen)? Probably using a wrong analogy here...like two planets colliding and result being shattered rocks? I hope this ain't a dumb thing to ask!
pot of gold over at the end of a rainbow (spectrum)
Zynda wrote:AmberG, I've got a few more questions regarding Neutron Stars. Hope its OK. And thanks for providing additional info including the excellent infographic of the discovery. I've heard that heavier elements such as gold are also product from massive star cores...
1. If a normal star is in very close proximity of a black hole and if the black hole is feeding off on the star, we get a streak of matter which then forms an accretion disk before going in to the black hole like what is rendered in the image below. Does this happen if a neutron star is in very close proximity to a black hole as well?
If the merger of the two neutro stars like the event that happened on Aug 17th, results in the formation of a new neutron star, does the new star retain the same density?
.....The authors also gratefully acknowledge research support from these agencies as well as by the Council of Scientific and Industrial Research of India, the Department of Science and Technology, India, the Science & Engineering Research Board (SERB), India, the Ministry of Human Resource Development, India,..
Actually LIGO team did not deny (until today) that the possible event was Neutron Star/Black hole merger. Yes this can take place.
(Like BH/BH, BH/NS, or NS/NS) and they will produce waves which LIGO can detect.
Amber G. wrote:Here is the historic Paper -- Hot of the press!
GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^4 years.
Amber G. wrote:
To best of our understanding -
Yes heavier elements come from star core's but only up till Iron.
- Elements H, and He were there / got created around big bang...
- Elements from Li to Fe (Iron) are formed inside stars (Carl Sagan's words "We are star stuff")
Elements heavier than elements came from Nova/super Nova/ or Kilonova -- neutron stars collide. {new discovery}
- Theories / observed spectrums of Super Nova explosions accounted for nearly half of heavier metals nicely but not everything fit
-till the recent observation (observed from spectrum) sheds new light. About half of the heavier elements (like Gold, Platinum, Uranium) are from Neutron start collision...
And this discovery is quite important.. very big deal.
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