Chanaka Rupasinghe

Nanolaser cancer therapy - A new spaser powered phothermal cell destruction method

noreply@blogger.com (Chanaka Rupasinghe) — Fri, 13 Feb 2015 01:49:00 +0000

Encircling tumors with a phalanx of miniature nanolaser could offer a new way to battle cancer,we propose as a new method of cancer treatment. Technically, the proposed device isn’t really a laser at all, but a spaser, with surface plasmons rather than light undergoing amplification.

Earlier last year, we proposed a different design, using graphene and carbon nanotubes. In this setup, a carbon nanotube would absorb the energy from a separate laser source and transfer it to the surface plasmons of a nearby nanoflake of graphene, creating the spaser effect. Pumping the spaser with 1200-nanometer light would cause it to output light at 1700 nm.

The nanotubes and graphene flakes could have antibodies or ligands attached to them that would draw them to the tumor. Once at the tumor, they’d self-assemble into a cluster of spasers.“You surround cancer cells with very tiny lasers, instead of nanoparticles,”

An external laser producing light between 1000 and 1350 nm could penetrate several centimeters of human tissue and act as a power source for the spaser cluster. The spasers would then deliver a concentrated blast of heat to the cancer cells. At the same time, the nanotubes could be designed to carry drugs to their target, hitting the tumor with a one-two punch.

Discovery article , IEEE spectrum article

Graphene- carbon nanotube spaser nanolaser introduced

noreply@blogger.com (Chanaka Rupasinghe) — Fri, 13 Feb 2015 01:36:00 +0000

We have been able to design the world's first 'spaser' - a nanoscale laser - made out of graphene and carbon. A spaser (surface plasmon amplication by stimulated emission of radiation) is effectively a nanoscale laser, or a nanonlaser. It has been touted as the future of optical computers and technologies. It could enable ‘nanophotonic’ circuitry, extremely small circuits far tinier than anything available today. This could usher in many technological advances including microchips hundred times more powerful than anything we have today.

'Our device would be comprised of a graphene resonator and a carbon nanotube gain element.'

'The use of carbon means our spaser would be more robust and flexible, would operate at high temperatures, and be eco-friendly'

See dailymail.co.uk article for more information

Spasers (nanolasers) - for the continuation of Moore's law

noreply@blogger.com (Chanaka Rupasinghe) — Wed, 10 Apr 2013 11:08:00 +0000

The emerging era of nanoplasmonics is expected to improve the speed and efficiency of optical devices by facilitating miniaturization beyond the limitations of conventional optoelectronics. It is seen that, as the technology matures during the last few decades, the utility and advantages of ‘electronics’ can be surpassed in certain instances by using ‘photons’. However, the used wavelength in most of these technologies is around the order of micrometers, thus the fundamental diffraction limit has intervened to constrain the advantages of scaling below the subwavelength stage. The solution is to use a hybrid particle state between electrons and photons which is known as ‘surface plasmon’ to operate in the nanoscale. The SPASER (Surface Plasmon Amplification by Stimulated Emission of Radiation), is the active nanoplasmonic device that can generate surface plasmons and amplify them similar to the lasers.

A video explaining the principle of operation of spasers:

Graphic credits :

1.Wikipedia
2.EquinoxGraphics.net

3.Bergman et al., Phys. Rev. Lett., 90:027402, Jan 2003

4.Chang et al., Opt. Express, 16(14):10580–10595, Jul 2008

5.Lisyansky et al., Phys. Rev. B, 84(15):153409, 2011

6.Zheludev et al., Nat.Photonics, 2(6):351–354, 2008

7. Seidel et al. Phys. Rev. Lett., 94:177401, May 2005

8. Noginov et al., Nature, 460(7259):1110–1112, 2009

Can there be both 'rational and irrational' numbers ?

noreply@blogger.com (Chanaka Rupasinghe) — Sat, 11 Jun 2011 06:27:00 +0000

Everyone knows, from the school, that square root 2 is irrational . I still remember the fashionable way in which my school teacher proved it. (for those who do not remember http://en.wikipedia.org/wiki/Irrational_number ). As all know, an irrational number cannot be written as a/b where a and b are integers. We know following facts which are proven in fashion in real analysis.

1. Any real number is rational or irrational
2. There are infinitely rational and irrational numbers
3. There are infinitely integers

'Can we say a given number is rational or irrational ?'. (If it is given in decimal points, number is rational for sure) . What I really mean is if I marked a random number on number line (see how irrational numbers are marked on number line at http://www.ehow.com/how_4455801_graph-irrational-numbers-number-line.html), who on the earth can say it is rational or irrational ? Since there are infinitely integers it can be a ratio of any two of them. Or since almost all the real numbers are transcendental (http://en.wikipedia.org/wiki/Transcendental_number) and all transcendental numbers are irrational, there is a higher probability of randomly marked number is being irrational.

Therefore until being confirmed (or observed) we cannot comment about the rationality of the number. But we can give a probability distribution for the rationality of the randomly marked number.

According to quantum mechanics, we can say this number is in superposition of states. i.e. the number is both rational and irrational. Described probability distribution is the wave function.

2011 -2020 a decisive decade for mankind

noreply@blogger.com (Chanaka Rupasinghe) — Sun, 13 Feb 2011 07:01:00 +0000

2011 is the first year of the 202nd decade which is to be end in 2020. This decade is going to be one of the decisive decades in human history due to many scientific, economic and political reasons. We had something similar decade in 1940-1950 where initial steps to the digital revolution kept with the invention of the transistor and Von Neumann and Alan Turing publishing their papers on stored program computers (First Draft of a Report on the EDVAC by Neumann and Automatic Computing Engine by Turing), first nuclear bomb was produced and world power was shifted to US and Russia.

This decade is similar because by 2020, we are approaching the end of Moore's law (doubling the performance of semiconductor fabrications in every other year ) , there will be plans replace modern computing with quantum computing, reaching the end of the era of fossil fuels and will be having earth with an unpredictable climate patterns.

End of Moore's law and quantum computing

While we are making the processors smaller and smaller, there is a limit that behavior gets unpredictable according to the laws of quantum mechanics. Then we will face a quantum leap or saturation. But recent developments in quantum computing and nanotechnology say we are not that unfortunate to face a saturation and coming to a dead end. However this will be decided by 2020. If we are going to replace modern computing by quantum computing, programming concepts will entirely be changed. New languages will replace C, C++ , Java etc.

End of fossil fuels

Despite the end of fossil fuels is not a proven fact, most nations have plans to replace fossil fuels by alternative sources in 2020. Sweden have plans to 100% fossil fuel eliminations in some regions and most other nations have plans cut off the fossil fuel usage by some percentage. Since we are reaching the end of the resource, finding alternatives is a must and otherwise it'll be serious energy crisis. This will be decided by 2020 and there we will be able to say whether we have to travel by carts or not.

Climate change

Since no proper agreement to limit global greenhouse gases came effective and US and China have not shown a commendable commitment, unpredictable climate patterns may occur by 2020. Even in this year, 2011 we have seen much of them all over the world. (Australia, Brasil, China etc.) . We will probably start experiencing the effects of global warming in 2020. There we will see the fate of mankind.

P.S. : New world order

Although shifting the world power from US to China may not happen there will be many world super powers unlike we had in last century. Anyway this matter is a topic of political scientists and does not suit the scope of this blog :)

image source : http://www.mesaresearchgroup.com

Science, Religion and Technology

noreply@blogger.com (Chanaka Rupasinghe) — Thu, 09 Dec 2010 10:54:00 +0000

Science, religion and technology have different objectives as,

Science - understanding the nature (or universe)
Religion- understanding nature and teach human the good and bad
Technology - make human's life easy

Their is no doubt that religions' all time mission on teaching human the good and bad is successful though many wars (in medieval ages and after in Europe, Crusades etc. ) and some terrorist activities (at present) have direct relationships with religions. But religion was a crucial factor in civilization. One might argue that UN's "The Universal Declaration of Human Rights" (http://www.un.org/en/documents/udhr/) can replace religion. But we've become civilized enough to prepare that 'universal whatever' as a result of religion. When talking about 'good and bad' ,all regions are similar. But the interesting part is religion's other objective 'understanding the nature' which overlaps with science.

Let's consider some concepts in religion

After life : All major religions (Christianity, Islam, Hinduism and Buddhism) possess some sort of an after life. In Hinduism and Buddhism one can be born again as human or animal. There is also a little difference between two regions. But for this discussion we ignore that. In other two regions human will be born in heaven or hell (different words may used )

Neither proven nor disproved scientifically

God/s : All 3 other religions except Buddhism teach that universe is created, maintained by God. In Hinduism, it is quiet different from other two. However the important thing is,

Neither existence nor non-existence of God is scientifically proven.

Even Einstein had talked many times about God. (God doesn't play dice). In his 'The Grand Design', Hawkings has some other thoughts. There are many famous questions of God. "What is god ?" , "Where does he stay ?" etc.

In addition to after life and god, there are many other concepts as well. But the important thing to notice is incapability of science to prove or disprove the concepts in religion. Does it imply that human still need religion ?

Current trend seem to be the technology which doesn't have problems with religion. Technology is to make our life easier and it doesn't need to find answers to unnecessary (?) questions. It only concerns "How to get a thing done ?" (programming, networking etc.) But there will be a day that technology needs go deeper in understanding nature. We'll be able to find the answers of religion that day.

Acknowledgement for image source : www.transalchemy.com

Using pattern recognition techniques for controlling dengue epidemic in Sri Lanka

noreply@blogger.com (Chanaka Rupasinghe) — Mon, 27 Sep 2010 10:50:00 +0000

Dengue epidemic has become a threat to Sri Lanka with a fast spread all over the country. The National Dengue Prevention Unit of the Ministry of Health, Sri Lanka has reported 30,607 cases of dengue and 221 deaths during January-September, 2010 . Situation is same for many other countries as well. The only way to get rid of this danger is the extinction of the cause-mosquitoes.

The lot of money which is spent for the prevention of this epidemic, can be optimized and maximum results can be gain if the pattern of the dengue vector-Aedes aegypti spread can be properly identified. Countries such as Singapore, USA and Cuba has used GIS (Geo Information Systems),statistical analysis and sensor network technologies to overcome this issue.

Currently, the foliole community (www.foliole.net) works on a pattern recognition technique based on fuzzy neural networks and k-means clustering. The neuro fuzzy system is used to estimate the influence of prominent factors affecting the spread of dengue vector, Aedes aegypti - precipitation, temperature, humidity and urbanization. Other socio-economic facts such as education of the people and poverty can also be considered. Meanwhile training data is prepared using k-means clustering for reported dengue cases.

Read the full article here : http://foliole.net/dengueprevention

Is Paul the wave function ?

noreply@blogger.com (Chanaka Rupasinghe) — Sun, 25 Jul 2010 05:15:00 +0000

Wave function is known as the mathematical model that used to calculate the probabilities of an observable. As an example wave function of an electron, Ψ(x,y,z) provides us the probabilities of finding it at the position x,y,z (actually modulus of squared wave function gives the probability) after the observation.

The phrase "after the observation" is very important in quantum mechanics. As an instance lets take the Schrödinger's cat. There is a cat inside a covered box and a gun is pointed to the cat. Triggering the gun is depended on a random event. Mechanism is gun will be triggered if a particular radiation happens within the period of the test. Hence there is a non-zero probability for both emission and non-emission. According to quantum mechanics, system is under quantum superposition until the observation is made. That is triggering and not-triggering at the same time which leads to the conclusion that cat is both dead and alive until it is observed.

When the observation is made, we can only see only one state, dead or alive. This is known as 'wave function collapsing'. From the superposition, it comes to a single state at the observation.

Lets go to the Paul's case. Lets assume the Germany vs Spain match is isolated so that quantum decoherance (avoidance of quantum superposition due to interaction/entanglement with environment) is avoided and no one observes the match. So match is in the superposition state of both teams are qualified for finals. Then we call our friend Paul, and give him the flags. He selects Spain and becomes a traitor.

Now, what happens ? we don't know the results of the match. But with the record of the Paul, we decide, chance of poor Germans to be in finals is 10% and 90% for spain. Isn't this the wave function ?

Then we go to Durban and open the gates of the ground to collapse the wave function. What we see is the verification of Paul's wave function...

Research paper based on ninithi published

noreply@blogger.com (Chanaka Rupasinghe) — Thu, 03 Jun 2010 12:20:00 +0000

Research paper based on the visualization part of ninithi was published at the "4th asia international conference on mathematical modelling and simulation" (AMS2010), Kota Kinabalu, Malaysia. Paper was titled as "3D modelling of carbon allotropes used in nanotechnology".

Research paper is available on IEEE Xplore

DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/AMS.2010.97

If you want more details about the paper please drop me an email to chanaka@ninithi.lk

Abstract :-
Graphene, Carbon nanoribbons, Carbon nanotubes and Fullerene (Buckyball) are allotropes of carbon which are widely used in Nanotechnology research due to their remarkable properties. Electrical and mechanical properties of those allotropes vary with their molecular geometry. Theoretically, an infinite number of such geometries do exist and it is impossible to physically prepare samples of all of them in the real world. This paper is based on modeling the atomic structures of those carbon allotropes with all the molecular geometries in 3D space, given variable user inputs to select the geometry, and customizing the view varying the angle and colours. Equations to derive the coordinates of the atoms, algorithms to derive the orientation of the bonds of the molecular structures and the manner in which the algorithms are implemented using java3D are described in this paper. Successful results were obtained after the implementation of the algorithms which are illustrated with few screenshots at the end.

ninithi released

noreply@blogger.com (Chanaka Rupasinghe) — Sat, 01 May 2010 03:56:00 +0000

ninithi which is a free and opensource modelling software, can be used to visualize and analyze carbon allotropes used in nanotechnology. You can generate 3-D visualization of Carbon nanotubes, Fullerenes, Graphene and Carbon nanoribbons and analyze the band structures of nanotubes and graphene.

For more information visit www.ninithi.lk and download the software free.

Facebook expands universe ?

noreply@blogger.com (Chanaka Rupasinghe) — Mon, 12 Apr 2010 12:56:00 +0000

What is universe ? Wikipedia says "The Universe comprises everything we perceive to exist physically, the entirety of space and time, and all forms of matter and energy"

There is an interesting word in this definition, "perceive" that is defined as "perception is the process of attaining awareness or understanding of sensory information". Perception is a subjective term. It is not the same way that I perceive and you perceive. Then we all should have an our own universe.

Let's define my universe as "Everything I know" where your universe is "Everything you know". I know that there exist objects (matter or energy) beyond the farthest object that I know and there is a time before the earliest event I know. Hence universe (I use the word universe for my universe) is infinite in size (the space time). (Remind the definition for plus infinity in mathematics that is "it is greater than any real number"). But the distance to the farthest object I know ever increases as I am getting to know more new objects. Hence my universe is ever expanding. (The expanding universe fact that have been found by the scientists can also be considered. There, the distance between me and the farthest object is continuously increasing). So we obtained same properties of the well known universe, infinite and expanding. But in a different way.

The universe is different for two persons. Assume the following scenario. You create a fake profile in facebook (let say Geetha), invite me and start to chat. For me, Geetha is a real person and she belongs to the universe. For you, Geetha doesn't exist in the universe. If people I know is another dimension of the universe,(we can define more dimensions in addition to x,y,z,t if we can not define the extra dimension in terms of x,y,z /independence ) it has been expanded with the existence of Geetha.

Though we used the terms "My universe" and "Your universe", only one universe exists. That is my universe or "The universe".

Can we build our theory by continuing in this way ? But we have to answer many questions. Like,

"What happens to the universe when I dead ?" or "How was the universe at my birth ?"

---(image source : wikipedia)

Nanotechnology modelling tools

noreply@blogger.com (Chanaka Rupasinghe) — Sun, 14 Mar 2010 11:32:00 +0000

Lanka Software Foundation, a non-profit and research oriented organization in Sri Lanka initiated a project in 2009 to develop opensource software to be used in nanotechnology research work. The idea was welcome by Sri Lanka Institute of Nanotechnology and agreed to assist in the progress.

The plan was to release a tool in 2010 and continue the progress in to a bigger project after the release. The inceptive project known as 'Ninithi' , is gradually approaching its completion. at the moment. The goal is to develop a tool to visualize and analyse widely used carbon allotropes in nanotechnology, Graphene, Carbon nanoribbons, Carbon nanotubes and Fullerenes.

The software also provides 3-D views of the molecular structures of those molecules and graphs illustrating electrical properties of them.

For more information visit the ninithi page

Developers : Chanaka Rupasinghe and Mufthas Rasikim

Anti-gravitons in the center of the earth ?

noreply@blogger.com (Chanaka Rupasinghe) — Thu, 03 Dec 2009 10:52:00 +0000

Anti-particle of the graviton is known as the graviton itself. Like photons. That is the accepted way. To find the anti-particle you have to sum up the quantum values to zero. You might also think that photon is light and there is no anti-light ? Is the same argument valid for gravitons ?

However If we found a material that emits anti-gravitons (Any hypothetical force that would repel masses ), it would be a huge boom in airline industry :) isn't it ? There is a good question. Are there such materials in the center of the earth to maintain the stability against a huge gravitational pull ?

We know that there is exists an equilibrium inside the nucleus (between neutrons and protons ) to maintain the stability under a large electric field. We might observe the same scenario for gravitational fields. Hence we would be able to find materials at the core of our planet which can be used to make flying objects with anti-gravity effect.

Challenge is to geologists. I don't know how deep we have gone through our planet or how complete the knowledge of earth's composition.

However existence of a particle (not necessarily anti-gravitons) that effectively alternate the graviton would be a great news.

Virtual Quantum Processor

noreply@blogger.com (Chanaka Rupasinghe) — Thu, 15 Oct 2009 05:39:00 +0000

Though usable (for people) quantum computers are not available yet, can we develop a virtual quantum processor same as the Java Virtual Machine (JVM) ? can we virtually implement virtual quantum registers, quantum processors etc on a general computer with a high processing power ? If it is done, this will be really helpful to understand and develop quantum algorithms which are going to rule the world of computing in coming decades.

But the problem is whether we can run quantum computations on a traditional processor. Hardware of traditional PCs may restricts the operations of quantum algorithms. The best example is random number generation. Study the random() functions written in languages like C,C++ or Java. They are not real random value generations but pseudo random.

Wave function is something that calculates the probabilities after the collapsing from superposition state. Virtually creating such a quantum superposition is a tough ask.

However if we can find a solution for this with some improvement of hardware, results will be invaluable.

Building a mathematical model for astrology

noreply@blogger.com (Chanaka Rupasinghe) — Thu, 13 Aug 2009 05:24:00 +0000

Can we do that ?

Finding a way to mathematically prove that there can exist a 'Method' or a 'procedure' similar to astrology which can predict the human behaviour or his future by studying the behaviour of 'Planets' or 'Some other objects' or 'Some other people' is quiet a difficult task. This may not be a proof for existing astrology.

It is fair enough to claim that "we can try to build a model that can predict the human behaviour with some accuracy". It is obvious that planets cannot influence people. But 'Planets change with people'. Not only planets but people change with people also.

What all we have to do is to find the correlation among the objects in universe and behaviour of people and identify the patterns.

Such a model can be called as 'Analytical Astrology' and will be highly useful in our day-to-day life if successfully implemented.

Is zero time processing or communication possible?

noreply@blogger.com (Chanaka Rupasinghe) — Mon, 27 Jul 2009 09:23:00 +0000

Evolution of the computer

From the Babbage’s differential engine realization and technology of the computer has been changing dramatically. Earlier it was a mechanical architecture used to implement algorithms and later it was transformed to architecture of logic gates that are made of electrical valves. Invention of the transistor led to an acceleration and IC technology (Introduced later) have been shrinking the size and increasing the processing power of the computer. With the introduction of parallel processing speed is multiplied while clock period remains the same.

Quantum computers

As the computers become smaller, size of transistors and gates become much smaller (A gate may be built of several atoms). To explain the behavior of matter in this scale we cannot use laws of classical physics. Therefore quantum mechanics is needed (Schrödinger Equations would be the governing equations instead of Newton or Maxwell laws).

Even though internal structure of the Bipolar Junction Transistor cannot be described without quantum mechanics, with suitable models, it can be explained by circuit theories. Therefore, logic gates that are currently used are called as conventional logic gates. As gates become much smaller it arrives to a point where they behave according to quantum principles. A computer that is made of such gates leads to a novel way of processing. New algorithms based on quantum principles will result faster and efficient processing.

Bits of quantum computers are known as Qbits. State of a conventional bit is either ‘0’or ‘1’ whereas state of a Qbit is ‘0’ or ‘1’ or ‘both 0 and ‘1’.The state ‘both 0 and 1’ is known as coherent

superposition. Quantum registers are more efficient than a conventional register. In an 8 bit conventional register, only 1byte can be stored at once whereas a quantum register can store

256 bytes (combinations of 8 bit numbers). Once quantum register is processed by a quantum processor outputs for all the combinations are given. This is similar to parallel processing. A system with n Qbits can perform 2ⁿ computations at once. Hence, quantum computer algorithms are more efficient than conventional algorithms. For instance, the complexity of factorization is exponential in conventional computing and polynomial in quantum computing.

Simple quantum logic gates of two Qbits have already been constructed in laboratories and it is believed that first quantum computer will appear before 2020.

Need for speed

Speed is the quest of the designers, and they always try on something to increase the speed atleast by a small amount. Because of these experiments, time taken for a specific micro operation to be executed becomes close to zero day by day. However, close to zero is not zero!

Unfortunately, there is a huge gap between zero and close to zero just like an energy barrier. In fact there is an infinite number of numbers exist between these two numbers!

L1= limε→∞0xε=0 and

L2=0/0 is indeterminate. Can be 0, 1, 1000, infinity or any value.

To complete 10¹⁵ micro operations, zero time processor takes no time and 10^-10s clock period(10GHz) takes more than a day. Therefore, ultimate target of the mankind would be to achieve zero time processing and zero time communication.

Upper bound of the relativity

According to the special theory of relativity maximum speed of communication is 3x10⁸ms^-1(i.e. speed of light) Maximum speed of a particle with non zero rest mass should be less than that. Since the diameter of an atom is about 10^-13m, clock speed of the fastest ever computer (Single processor) built by existing technologies will be well below than 10¹⁸ GHz .Disappointing!

EPR photon pair

As a result of a thought experiment developed by Albert Einstein (E), Boris Podolsky (P) and Nathan Rosen (R) EPR paradox was introduced. This is one of the most discussed phenomena in quantum mechanics.

A basic hypothesis in quantum mechanics is that all the observables cannot be known at 100% accuracy. If momentum of a system is measured then its position is affected, for energy its time is affected. Another observable is the spin of a particle (Related to the angular momentum ofthe particle). Particles have spin in x, y, z directions and they are given as ‘up’ or ‘down’.According to quantum principles, the spin of a particle cannot be measured in two directions at the same time.

Using the aforementioned facts, three physicists made a paradox. Out of the discoveries, one is interesting. A photon pair (EPR photon pair) should communicate each other. When two photons are communicating (Even if they travel in opposite directions), speed of a photon relative to another photon is the speed of light. Thus, the communication should be faster than light (If it is possible). So is that a way to make our dream a reality?

Communication via an extra dimension

Lets consider five dimensions that are x, y, z, time and one extra dimension (A recent idea about the universe is that it is a five dimensional black hole). For the ease of analysis, entire 3D Euclidian plane (i.e. R³ vector space) is mapped in to one direction, which is position r, and time is perpendicular to r.

For any object (Wave or particle) to travel from r1 to r2 takes some time. That implies always,

∂t/∂r >=0

This happens because any object that obeys wave particle duality has a property related to time. If we could map that property to a time like dimension ( let say w) then w, t, and r perpendicular to each other. Therefore time taken to travel from r1to r₂ is zero.

The most challenging thing is finding a way to transform properties of t to properties of w. It is possible only if we could find any object that has no time related property. It should be anything that does not obey the wave particle duality. Once it is done zero time processing or communication is no longer a dream.

Does our mind obey the wave particle duality ?