# How to encrypt a message in the afterglow of the big bang

If you’ve got a secret to keep safe, look to the skies. Physicists have proposed using the afterglow of the big bang to make encryption keys.

The security of many encryption methods relies on generating large random numbers to act as keys to encrypt or decipher information. Computers can spawn these keys with certain algorithms, but they aren’t truly random, so another computer armed with the same algorithm could potentially duplicate the key.

An alternative is to rely on physical randomness, like the thermal noise on a chip or the timing of a user’s keystrokes.

Now Jeffrey Lee and Gerald Cleaver at Baylor University in Waco, Texas, have taken that to the ultimate extreme by looking at the cosmic microwave background (CMB), the thermal radiation left over from the big bang. Continue reading How to encrypt a message in the afterglow of the big bang

# What statistics can tell us about strategy in tennis

Theoretical result for the probability to have a result from -7 to 7 in a tiebreak considering that the probability to win(lose) a point is 0.5. Horizontal axis is the difference of points from a given and other players. Positive values mean victories and negative losses

I. Y. Kawashima, R. S. Marques de Carvalho, O. Helene, M. T. Yamashita
In this paper we analyse tiebreak results from some tennis players in order to investigate whether we are able to identify some strategy in this crucial moment of the game. We compared the observed results with a binomial distribution considering that the probabilities of winning or losing a point are equal. Using a χ2 test we found that, excepting some players, the greatest part of the results agrees with our hypothesis that there is no hidden strategy and the points in tiebreaks are merely aleatory.

# Adding Quantum Rooms to the Hilbert Hotel

An optical experiment realizes one of the room-changing operations in the Hilbert Hotel—a fictitious establishment that illustrates some perplexing properties of infinity.

The Hilbert Hotel is a famous mathematical paradox about an imaginary inn with infinite rooms. Even when completely full, vacancies can be made through coordinated room switching. You obviously won’t find this place in any guidebook, but the energy levels in a quantum system can mimic the rooms in the Hilbert Hotel. In an experiment using optical modes of a laser beam, researchers perform a “room switching” operation that creates a vacancy by transforming one quantum state into another.

In 1924, the mathematician David Hilbert highlighted the counterintuitive nature of infinity with a tale about a hotel with an infinite number of rooms, each having a single occupant. If a new guest arrives, the hotel manager can create a vacancy in room 1 by moving all occupants up one room ( nn+1). If infinite guests arrive, the manager can open up all the odd-number rooms by shifting everyone to twice their room number ( n2n).

In a recent study, John Jeffers from the University of Strathclyde, UK, and his colleagues showed how to perform the nn+1 shift in a quantum system with an unlimited number of energy levels. The same group has now extended this work to the n2n shift using a laser beam with discrete orbital angular momentum modes, or “rooms,” which are characterized by petal-like intensity lobes. The team demonstrated a procedure that changes the room n state to the room 3n state (but it also works for other multiplication factors like 2). This operation could be useful in creating frequency gaps between multiple channels before combining (or multiplexing) them into a single communication signal.

# Measuring the Forces in a Knot

Knot physics unraveled. A double overhand knot (n = 2) is shown here tied with rope. Researchers were able to relate the forces in the knot (tension, friction, and bending stiffness) to the topology (number of turns, n). The experiments were performed with wire (not rope), in which the bending stiffness provides greater resistance to the closing of the knot loop.
M. K. Jawed et al., Phys. Rev. Lett. (2015)

Knots have such sharp twists and turns that researchers have had trouble determining precisely how a knot’s shape affects the forces within it. But now a team has theoretically modeled a simplified knot, showing the effects on the internal forces when adding or subtracting a turn. The theoretical calculations matched the team’s experiments in which thin metal wires were tied into large open knots. The results may guide future work in characterizing more complicated knots that are pulled small and tight. Continue reading Measuring the Forces in a Knot

Aside

# Is poker a game of skill or chance? A quasi-experimental study

Meyer G, von Meduna M, Brosowski T, Hayer T.
Due to intensive marketing and the rapid growth of online gambling, poker currently enjoys great popularity among large sections of the population. Although poker is legally a game of chance in most countries, some (particularly operators of private poker web sites) argue that it should be regarded as a game of skill or sport because the outcome of the game primarily depends on individual aptitude and skill. The available findings indicate that skill plays a meaningful role; however, serious methodological weaknesses and the absence of reliable information regarding the relative importance of chance and skill considerably limit the validity of extant research. Adopting a quasi-experimental approach, the present study examined the extent to which the influence of poker playing skill was more important than card distribution. Three average players and three experts sat down at a six-player table and played 60 computer-based hands of the poker variant “Texas Hold’em” for money. In each hand, one of the average players and one expert received (a) better-than-average cards (winner’s box), (b) average cards (neutral box) and (c) worse-than-average cards (loser’s box). The standardized manipulation of the card distribution controlled the factor of chance to determine differences in performance between the average and expert groups. Overall, 150 individuals participated in a “fixed-limit” game variant, and 150 individuals participated in a “no-limit” game variant. ANOVA results showed that experts did not outperform average players in terms of final cash balance. Rather, card distribution was the decisive factor for successful poker playing. However, expert players were better able to minimize losses when confronted with disadvantageous conditions (i.e., worse-than-average cards). No significant differences were observed between the game variants. Furthermore, supplementary analyses confirm differential game-related actions dependent on the card distribution, player status, and game variant. In conclusion, the study findings indicate that poker should be regarded as a game of chance, at least under certain basic conditions, and suggest new directions for further research.