Cosmic ray particles capable of penetrating even the densest buildings or underground structures can provide an essentially foolproof timing system for synchronising high-frequency trades in the world鈥檚 international stock exchanges.
High-frequency trading is a method involving powerful computers that allows traders to analyse markets and make large numbers of profitable transactions each second 鈥� and in order to work, the method requires stock exchanges to be synchronised with nanosecond precision. Financial firms currently rely on time servers synchronised by GPS and other global navigation satellite systems to provide that precision, but these approaches are vulnerable to spoofing or GPS jamming.
at the University of Tokyo has devised an alternative synchronisation system based on detecting muons 鈥� high-energy particles created when cosmic rays strike Earth鈥檚 atmosphere. Tanaka has demonstrated how the approach can cover a circular area equivalent to the main financial centres of cities such as Tokyo, London and New York.
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鈥淭he current cosmic ray system enables 鈥榳ireless transaction鈥� by taking advantage of the cosmic signal鈥檚 high penetrating power 鈥� even through thick rock,鈥� he says.
Tanaka developed and tested his system with muon detection stations located in three separate buildings in the outskirts of Tokyo. As cosmic ray particles shower down on each station鈥檚 muon detector, a separate device measures the time of arrival and issues a timestamp. The timestamps are transferred via encrypted WiFi signals from one station 鈥� acting as the main time server 鈥� to the other 鈥渃lient鈥� stations, so that the client clocks can be adjusted and synchronised based on the difference between the timestamps.
The resulting experiment showed the system could provide timing synchronisation to a circular area with a diameter of 360 metres 鈥� an area that would cover all of the computers in one of the world鈥檚 large stock exchanges and most buildings in a given financial district. Tanaka says this could be extended, in principle, to cover an area with a diameter of 1 kilometre. The demonstration had a synchronised timing accuracy of less than 150 nanoseconds, which means it meets regulation standards for financial transactions.
This could even provide a cheaper alternative to GPS-synchronised systems. A typical GPS-based time server may cost between $20,000 and $30,000, whereas each cosmic ray station server may cost just $8000, says Tanaka. Financial firms must also install fibre-optic wires connecting the GPS-synchronised server on the outside of a stock exchange building to all of the computers inside.
Both Italy and the UK have set up dedicated fibre-optic lines for transmitting timestamps directly from atomic clocks to financial district buildings 鈥� but the cosmic timing synchronisation could once again prove much cheaper by comparison.
鈥淏y replacing the fibre optic cable infrastructure with a timing signal based on natural cosmic rays, the approach removes聽the need for the costly installation,鈥� says at Geoptic, a company developing muon imaging systems in the UK.
The time synchronisation for Tanaka鈥檚 system was initially proven over a period of three days. But additional testing conducted with the National Metrology Institute of Italy has already shown how that period could be extended to more than 20 days 鈥� and a next step would involve testing the stability of the system over a year or more.
鈥淭he system is resistant to jamming and spoofing and suitable for indoor, underground and underwater applications,鈥� says at the National Metrology Institute of Italy.
Cerretto and his colleagues are currently evaluating the measurement limits of the cosmic timing synchronisation system and seeing whether it can work in concert with GPS to extend timing synchronisation capabilities to environments beyond the reach of GPS.
Scientific Reports
